Check the listing for details. Tactical 45 Degree Offset Back Up Sights Rapid Transition BUIS. Condition: New. Listed at 19.75 USD. These sights mount directly to a weapon's Picatinny rail, offset from center by approximately 45°. This unique offset position makes transitioning from optical to iron sights simply a matter of quickly canting the weapon with your wrists and locking on to the target. One weapon,two missions.A simple turn of the wrist transitions from the primary sight to the iron sights. This simple and innovative idea allows for very quick acquisition of both long range and close range targets. FeaturesUltra-Durable: Machined from polymer alloy bar stock, and light weightMil-Spec Hard Anodized finishSame bore height as standard sightsAmbidextrous: can be mounted for Left or Right hand shooters45 degree offsetLow profile over picatinny rail only rising 2/10th of an inch so that it does not interfere with your primary opticsMounts directly to the top picatinny rail of your rifleNo Special Tools Required: only uses a flat head screw and can easily be done in the fieldCompatible with military IR Laser/Illuminators, front sight designed to clear beam pathRapid Transition Backup Iron Sights attach to any mil spec 1913 picatinny rail. These sights do not require any special tool for installation. The sight base attaches to the rail using only a flat head screw (which also fits small coins) for incredible convinience! The sights can be positioned on either side of the weapon, accomodating both right and left handed shooters. Weight : Front Sight 1.2oz and Rear Sight 2.5oz