The KeyMod system consists of two parts: the KeyMod slot and the KeyMod nut. The KeyMod system allows a user to place MIL-STD-1913 rails wherever needed (even in the 45° positions at times). The goal is to eliminate the need for the rail to be fully outfitted with 1913 rails covering the entire handguard. The KeyMod system is intended to be used as a direct attachment method for firearm accessories such as flash light mounts, laser modules, sights, scope mounts, vertical grips, rail panels, hand stops, barricade supports, and many others. KeyMod is an open-source design released for use and distribution in the public domain in an effort to standardize universal attachment systems in the firearm accessories market. The name 'KeyMod' was coined by Eric Kincel (then working for VLTOR Weapon Systems) following the naming trend of other VLTOR accessories with the suffix 'Mod' meaning modular, and 'Key' being a reference to the key-hole profile of the mounting slots.

The concept was first created by VLTOR Weapon Systems of Tucson, Arizona, and released through Noveske Rifleworks of Grants Pass, Oregon, before being published open sourced in the public domain for adoption by the entire firearms accessory industry. KeyMod is a universal interface system for firearm accessory components designed to supersede the MIL-STD-1913 accessory rails.

Keymod accessories midway