Arex's Rex Zero 1 pistol complies with strict military standards for reliability. Its frame is constructed of T7075 aluminum with steel locking block inserts and a hardcoat anodized finish. The nitrocarburized slide and cold hammer forged barrel are made from solid steel. The Rex Zero 1 has high profile white dot sights, ambidextrous safety, loaded chamber indicator, full length slide rails, and a large trigger guard for the use of gloves. Tactical models feature a threaded barrel with 1/2"x28 threads and include the ROR (Rex Optics Ready) system with four plates for optics attachment. This model has a black finish and 20-round magazine capacity.