Magpul takes their back up sight to the next level with the MBUS (Magpul Back Up Sight) Gen 2. The weight has been reduced to a mere 25 grams and sits at just 0.47” high when folded and measures 1.38” at its widest point. Just like its predecessor the MBUS 3 utilizes a spring-loaded operation, allowing them to be deployed instantly and accommodates left and right-handed users. Once mounted, the MBUS Gen 2 sits at standard AR height when deployed, and windage/elevation adjustments can be made without the use of tools. Available in both front and rear sight configurations. Features: Lightweight & Durable Polymer ConstructionSpring Loaded Operation Ambidextrous Mounts via 1913 Picatinny Rail Magpul Industries MBUS Gen 2 Polymer Picatinny AR15/M16 Flip-Up Black Rear Sight MAG248BLK