Micro Fight Chassis Mk4 - Lightweight. Modular. Mission Ready. The Spiritus Systems Micro Fight Chassis Mk4 is the foundation for building a lightweight, modular chest rig or placard that adapts to any mission. This versatile platform integrates seamlessly with the entire Spiritus accessory suite, making it ideal for a range of loadouts from low-vis to full kit. Inside both compartments, soft loop Velcro allows you to position mission-essential inserts and accessories exactly where you want them. The rig’s improved profile supports up to six 5.56 mags or four 7.62 mags, plus combinations of rifle and pistol magazines. A large 5 by 9-inch hard loop Velcro panel on the back ensures rock-solid integration with back panels, SACK pouches, Expander Wings, and plate carriers like the LV119. The Mk4 can also accommodate a tourniquet using the integrated grommets and optional Universal Retention Kit, giving you quick access to life-saving gear. Why We Love ItThe Mk4 is the ultimate blank canvas for your gear. Whether you're scaling down for covert ops or scaling up for a full assault kit, this chassis gives you the freedom to build your ideal setup without compromise. Features: Compatible with Spiritus Systems inserts, flaps, wings, and pouches Soft loop Velcro lining inside for custom mag insert placement 5” x 9” hard loop Velcro on back for plate carrier mounting Integrated grommets for tourniquet mounting Supports six 5.56 mags or four 7.62 mags Ultra-low-profile design ideal for low-vis ops Lightweight and rugged for mission-critical use Made in the USA Note: This listing includes the Mk4 Chassis only. Shoulder straps, back strap, mag inserts, flaps, and other accessories are sold separately. You will need additional components to run this as a complete chest rig or placard.