Ade Advanced Optics Polymer Front and Rear 45-Degree Rapid Transition BUIS Backup Iron Sight Impact resistant polymer construction provides light weight and resists operational abuse Same height above bore as standard-issue M4 / M16A4 sights 1/2 MOA elevation and windage adjustments Ambidextrous sights easily and securely mount to Picatinny rails using a flathead screwdriver Light weight Low-profile sights extend only .2" above top rail, don't interfere with primary optics or military IR illuminator /laser sight