Chest Rig Review: Spiritus Systems Micro Fight Mk.IV

Using Velcro on tactical gear is hardly a new concept, but to make it a central element of the design and to use almost nothing else? Whoa, there’s an idea!

So how does a company come from nowhere, with a product that’s so different to the norm, and somehow produce something that’s now considered a benchmark of modern chest rig design?

Formed in 2013 by 82nd Airborne veterans Zane Vogel, Adam Holroyd and Adam’s wife, Nichole; Spiritus Systems has developed and put to market a number of well received products, none more so than the signature Micro Fight Chest Rig.

Despite being a relatively new company on the scene, Spiritus Systems has rapidly become a household name within the tactical gear world and for some people, an absolute obsession.

Patches are a part of my religion…

The Spiritus Micro Fight range exists not only as a mere chest rig or placard, but as a suite of components developed to work together as needed and using Velcro as its primary attachment method.

One key benefit to this method is it’s adaptability for different load carriage requirements, and the ease at which it can be reconfigured to fit almost any end user need.

Within this review I’ll cover the basic chest rig package set up, comprising the following components:

  • Mk.IV Chassis
  • 5.56 Magazine Insert
  • Micro Fight Full Flap
  • Fat Strap (H Harness)
  • Back Strap

In addition, I’ll briefly look at two other popular additional parts to the system:

  • Pistol Magazine Insert (double)
  • Micro Fight Half Flap

The last two items are not included as part of the basic chest rig package but are available separately, as is the case with all individual Micro Fight components.

Before we continue, I owe a massive thank you to my good friend Alex from GWOPGOONS for lending me his Spiritus set up, it was provided as a favour to me alongside his JPC 2.0 (reviewed here). I’ve borrowed it for literally months now and has given me time to properly test and review the kit, meaning that I didn’t need to rush the review. (Sorry for all the cat hair! 😽)

Micro Fight Chassis MkIV

The primary component of the Fight Light system is the Chassis, a central hub to which everything attaches.

The chassis is a simple enough design; Simply put, it consists of a pair of rectangular box shaped sleeves stitched to one another. The innermost sleeve sits tight against the wearers body and the outer sleeve sits on the front face of the rig. A loop field sits on the inner face of each sleeve, designed to allow the attachment of a plethora of inserts, flaps and organisers.

The front pouch is slightly smaller than the rear from top to bottom, but remains the same width as the rear pouch. Due to this difference in height, magazines placed in the front pocket can be seated higher than those in the back. Not by much, but enough to aid in drawing a magazine from the front row without being obstructed by those in the back.

Six webbing loops and their associated buckles allow the attachment of the chassis to the included “Fat Strap”harness, or even directly to a plate carrier (Many plate carriers now come with suitable attachment points for micro rigs). You even have several third party options such as harnesses such as used on Crye’s AirLite or Haley’s D3CR chest rigs.

A pair of female buckles sit on the top of the chassis, one each side for the attachment of shoulder straps or to mount to a compatible carrier. A further four male buckles sit on the corners of the chassis, positioned to keep the chassis firmly in place and providing anchor points for the shoulder and back straps.

The rear of the chassis is dominated by a large hook field, ready to be used to attach the chassis to virtually any loop fronted plate carrier. The Mk.IV’s panel is bigger than that used on the Mk.III Chassis, providing slightly more security when attaching to a plate carrier. A blanking panel is provided for the hook field to allow comfortable standalone use.

A single drainage grommet sits on the bottom of the rear sleeve compartment, with an additional pair on the bottom of the front compartment. These grommets offer adequate drainage and can be used as attachment points for a tourniquet using Spiritus’ own Universal Retention Kit.

Rifle Magazine Insert (5.56 Triple)

The 5.56 magazine insert is undoubtedly the most commonly used component (aside from the chassis itself), a simple design comprising of an elastic band that’s sewn vertically into three sections.

This band is held firm within the chassis via squares of hook field Velcro that are stitched directly to the elastic. The insert is open bottomed and lacks a stirrup bar, allowing taller items such as small personal role radios etc to fit within the very same sleeve as rifle magazines.

The retention is good and doesn’t require any additional guard against magazines falling out, they’re also relatively resistant to wear, but as they’re removable, it’s not unrealistic to consider them as a perishable/replaceable item should you ever need to in the future.

Micro Fight Full Flap

The Full Flap can be used to cover the front section, turning the front sleeve of the chassis into a single large pocket. Although it’s often discarded in favour of other options, if you’re looking to keep the rig minimal or need the entire front pocket covered, it’s actually a great addition.

A small webbing loop provides a pull tab to help the wearer open any pockets and a loop field prevents any noticeable loss of loop real estate whilst being used.

Micro Fight Fat Strap

The “Fat Strap” is how Spiritus Systems refer to their H harness system, comprising of a non-padded, low profile section of cordura which is formed into an H section (the upper/rear “arms” of the H being made from standard 1” webbing).

The Fat Strap includes a pair of female buckles to provide attachment to the top of the Chassis, it also has a few other nifty features that help the rig remain low profile whilst offering a few choice attachment points for gear and equipment… Each female buckle is tucked behind an elastic retainer, these stop the shoulder straps from tucking up under themselves (as can happen with some other rigs), a nice touch and one I’d certainly incorporate into any future bespoke harness I have made.

A pair of horizontal webbing strips flank an additional elastic retainer on the upper section of the harness’ shoulder straps, these are perfect attachment points for PTTs or small navigation devices such as the Garmin Foretrex GPS… They also make great retainers for comms cabling or hydration tubes.

On the rear of the Fat Strap is a section of loop Velcro to allow attachment of marking strobes/patches. Be careful what you place here, it could come into contact with your weapon sling and get ripped off.

The Fat Strap has enough excess webbing on its upper arms to allow for a wide range of adjustment, catering for most body types as well as those who wish to use a Micro Fight chest rig over covert body armour.

Micro Fight Back Strap

The Back Strap is a simple 1” webbing strap, both ends terminating in a male buckle. The excess webbing is held in place via a pair of triglides and each end of the webbing is heat sealed to prevent fraying. Some manufacturers will fold and stitch the ends of their webbing, but this is case in point that it’s not necessary.

So that rounds up the basic chest rig package, but before I get into the overall pros and cons of the chest rig and give you my overall summary, I’ll show you some additional bits that are commonly used to expand upon the chest rig’s capabilities.

Pistol Magazine Insert (Double)

One of the most commonly bought additions to the Micro Fight is the Pistol Magazine Insert (Double), this allows you to carry a pair of Glock (or similarly sized) pistol magazines. These are closed at the bottom, meaning that short magazines cannot fall through the bottom of the insert, it does mean that taller magazines will stand proud of the insert, but testing with regular sized Glock and Beretta magazines, I’ve not noticed any retention issues so far.

They are held in place (front and back) with a full length strip of hook Velcro, meaning that they are pretty stable from top to bottom and tend to resist lateral movement very well too.

Micro Fight Half Flap

The Half Flap is a logical pairing with the double pistol insert, the same design as a full flap, simply half the width. Using the half flap allows you to convert one half of a chassis sleeve into a pocket whilst leaving the other side free for one of a number of options such as a single rifle mag pouch or a double pistol magazine (as shown in this review).

There isn’t much more to say about the half flap other than it’s a solid choice and remains the simplest way to retain small devices such as mobile phones or rite in the rain notepads… Or something to keep the chills away on a cold lonely night.


Overall, the Spiritus Systems Micro Fight is a fantastic carriage option, managing to be incredibly customisable whilst remaining incredibly simple. There really isn’t anything novel about the way it’s made or any secret ingredient that makes it special, but it still manages to be one of the best chest rig options available despite it’s simplicity.

The quality is good overall, but for the price you’d expect that. The material and hardware are also of very good quality and shouldn’t let you down, even when abusing the chest rig. And combined with it’s no-nonsense design, this makes it a hard product to beat.

Is it worth getting? What makes this better than one of the many clones and copies on the market? Well, it’s down to QC. With a product so simple, it’s easy to go ahead and buy a Chinese clone at a third of the price and think you’re beating the system, but what you risk is buying an item that uses poor materials/hardware, has almost no quality control and lacks the tolerances that make this product work.

When it fails, and I have personally seen buckles and stitching fail on clone Spiritus and Haley rigs, you’ll be left with a £60 hole in your wallet and a shit weekend trying to carry mags in your pockets. You’ll always have copycats when you do something well, the Spiritus design is no exception, everyone from TMC to Viper have got their dirty little rat claws on the design and managed to copy it, some with acceptable results, others… Less so. Do yourself a favour and buy genuine, it’s the only way to be sure.

In use, the chest rig performs very well. Attaching it to either a Ferro Slickster or Crye JPC 2.0 provides a good amount of storage, right where you need it. The modularity of this design means that you’re as much to blame for any carriage issues as Spiritus themselves, there’s a real danger that people fall into, adding too many pouches and add ones to a micro rig, when all you really need is Ammo, Med Kit, Beer and Dope.

When configured as a standalone chest rig, it’s comfortable and light. The straps providing enough support for the rig’s modest payload, but not feeling underwhelmed when the chest rig is expanded upon with dangler pouches, expander “wing” pouches or even modular chassis carriers such as Spiritus’ own “The Thing 2”.

The Thing 2 expands upon the load carriage ability of the Spiritus Micro Fight Chassis, mounted here with their small GP pouch and a Nalgene carrier.

Negatives? Well it’s Velcro. Velcro tends to lose some of its effectiveness when very wet or dirty. This doesn’t actually present as many issues as you’d think, the Velcro elements are generally static when out in the wild, the inserts shouldn’t need re-sticking unless reconfiguring the entire rig and even removable sections such the full/half flap have a significant area to ensure you get some grip, no matter how filthy the rig is.

The only other negative is much the same as any other modular system, it’s only as good as the guy sticking it together. It will take a few goes to find a set up that works for you, but that’s also half the fun. As mentioned, you should be wary of adding unwanted bulk to this rig… It’s called a Micro Fight for a very good reason.

There’s very little you can’t do with the Micro Fight, with Spiritus’ own range of add ons being complemented by an ever-growing number of aftermarket accessories from the likes of AXL, Microbat and even through using competitor products (such as The Reptile House’s use of a Crye Airlight Harness), you should be able to find a set up that provides you with everything you need.

The Spiritus Mk.IV (right) hybridised with Crye’s AirLite harness. Photo Credit The Reptile House

The big question though is, would I recommend it to a friend? Well… Yeah.

I actually ended up buying a complete Spiritus Micro Fight set up in Ranger Green from Tactical Kit during a recent re-stock, so it’s fair to say that after getting hands on with the rig, I really didn’t want to give it back!

The Spiritus Systems range is available directly from their own site for US, Canada and Mexico customers (and those serving abroad with an active APO/FPO/DPO address). For those outside North America, Tactical Kit UK are the approved retailer for Europe and depending on your location, can ship to most of the world.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s