The .45 ACP is loud and proud by nature but certain scenarios require a quieter approach. It ups the ante of the R1 Enhanced's features with a threaded barrel to easily accept silencers. Also adds a tall two-dot rear sight for use with a silencer and two 8-round magazines with bumper pads. - Tall two-dot sight system allows use with silencer installed - Front and rear slide serrations - Beavertail grip safety with checkered memory bump - Enhanced hammer - 3 hole adjustable match trigger - Enhanced wide thumb safety - Flat checkered mainspring housing (20 LPI) - Match-grade stainless barrel with threaded muzzle and thread protector - Front grip strap serrations - Custom grips with thumb groove and ambi cut - 8-round magazines with bumper pad (2) - Barrel thread pitch (.578-28)