HSS AR15 AR 15 Front and Rear flip up Rifle 45 Degree Offset Micro Rapid Transition BUIS Backup Iron Sight Ambidextrous sights easily and securely mount to Picatinny rails using a flathead screwdriver Machined from lightweight, extremely durable 7075 aluminum, Mil-Spec hard anodized Same height above bore as standard-issue M4 / M16A4 sights Fast shippment from our California's warehouse, delivery time about 2-5working days.