XTS Polymer Flip-Up Rear Sight for Picatinny Rail, Black The XTS FRS rear sight is a black polymer flip-up sight for Picatinny rails. Its rear-sight role and folding profile identify it for shoppers comparing rail-mounted sight components. The flip-up design provides a raised sight position and a folded profile. This item is the rear sight component, so its role should be considered alongside the rest of the intended sight arrangement. Polymer construction and black color round out its basic specifications. Key Features Sight position: Rear Design: Flip-up Mounting interface: Picatinny rail Specifications Brand: XTS Model: XTS-FRS Material: Polymer Color: Black Shop the XTS Polymer Flip-Up Rear Sight for Picatinny Rail, Black at BattleHawk Armory.