Eye Catching and Self-Centering 4-Dot Tritium Sights Get You on Target Faster Being able to see your sights in all lighting conditions is critical. Tritium illumination is the battery free option for low-light sight options. The Meprolight FRBS Front & Rear Flip Up backup sights with tritium inserts are always ready when you need them. If you are running an optic that uses batteries on your rifle then backup sights are highly recommended. The low-profile design keeps the sights out of the way until needed. The spring-based locking mechanism will not break or deform when deploying the sights. The fiberglass reinforced polymer and metal construction is lightweight, durable and able to withstand heavy recoil and hard use. Elevation and windage are manually adjustable and no tools are needed. The sights are compatible with MIL-STD 1913 Picatinny rail systems. Meprolight FRBS Front & Rear Flip Up Sights Tritium Specifications and Features Meprolight Item Number 403240 4 Dot Tritium Insert Rear Sight Hyper Bright Front and Orange Rear Low Profile Lightweight Spring-based Locking Mechanism Fits Picatinny Rail Fiberglass Reinforced Polymer and Metal