The Special Operations Peculiar MODification (SOPMOD) kit is an accessory system for the M4A1 carbine, CQBR, FN SCAR Mk 16/17, HK416 and other weapons used by United States Special Operations Command (USSOCOM), though it is not specific to SOCOM. The kit allows US Special Operations Forces (US SOF) personnel to configure their weapons to individual preferences and mission requirements. The program dates back to September 1989, when the Special Operations Special Technology (SOST) Modular Close Combat Carbine Project was founded. This was the first program to standardize components from the 1970s/1980s era of "duct tape and hose clamps". The Material Need Statement (MNS) was signed in May 1992 and, by September 1993, the Operational Requirements Document (ORD) for the program was validated. Responsibility for the program was then assigned to the Naval Surface Warfare Center Crane Division. The SOPMOD kit is composed mostly of non-developmental items and commercial off-the-shelf (NDI/COTS) accessories packaged together to support four M4A1 carbines. It allows for the attachment of any Picatinny compatible accessory that fits the length of the weapon. Block I The original SOPMOD Block I kit included the following: Knight's Armament Company (KAC) Rail Interface System/Rail Adapter System (RIS/RAS) forearm with rail covers of various lengths. KAC Vertical Foregrip (VFG) KAC 300m backup iron sights (BUIS) Trijicon TA01M4A1 4x32mm Advanced Combat Optical Gunsight (ACOG) Aimpoint ECOS-N (Enhanced Combat Optical Sight-Navy), a variant of the CompM2 using the Wilcox Aimpoint CompM mount instead of the standard issue QRP mount Tactical Ordnance and Equipment Improved Combat Sling, which allows for secure cross body/patrol carry. Precision Reflex, Inc. (PRI) M69 Bracket Mount for the AN/PVS-14 night vision device. Only two of following were included per kit: Insight AN/PEQ-2 Infrared Target Pointer/Illuminator/Aiming Laser (ITPIAL) Insight Visible Light Illuminator (VLI) Trijicon RX01M4A1 1x24 Dual Illuminated Reflex Sight KAC NT-4 Quick-Detach Sound Suppressor (QDSS) kit Only one of the following was included per kit: M203A1 Grenade Launcher with a 9-inch barrel KAC M203 Grenade Launcher Quick Release Front Bracket Quick-attach M203 Grenade Launcher Leaf Sight Insight AN/PEQ-5 Carbine Visible Laser (CVL) Insight AN/PAQ-4 Infrared Aiming Light AN/PVS-17A Mini-Night Vision Sight AN/PSQ-18A M203 Day/Night Sight Carrying/storage case for kit accessories Part of the SOPMOD Block I (but not always issued with kits): Gas-deflecting charging handles (presumably the PRI M84 Gas Buster Charging Handle with Military Big Latch) Extraction Parts Set #2 Redi-Mag Lewis Machine and Tool Company (LMT) Sloping Cheekweld