The Special Operations Modifications (SOPMOD) were developed to increase the operational effectiveness of the M4A1 carbine through improved target recoginition, acquisition and hit quality, during day or night, from close quarters to 500m. It is commonly used by US Special Operations Forces. This version comes with a single and full auto trigger group, ACOG 4x sight and a forward handgrip. The QD sound suppressor reduces noise by 30Db.