Windham Weaponry’s Varmint Exterminator semi-automatic features a gas impingement system and a 5-round magazine (accepts all std. sizes). The manual safety lever has indicator markings on both sides of receiver, the M4A4 type flat top upper receiver has optics riser blocks. The receiver is made of forged 7075 T6 aircraft aluminum with aluminum trigger guard and a hardcoat black anodize finish. It also features a 20 fluted barrel made from precision 416R Stainless Steel and a matte finish.