This Leupold Mark 4 IMS Integral Ring Insert makes it easy to attach your scope to your AR style rifle. The Mark 4 IMS from Leupold gives you the correct scope height and eye relief, plus an extremely rugged and durable construction quality that Leupold mounts are known for. The Leupold Mark 4 Ring Insert allows you to have the rifle scope in the perfect location to maximize accuracy and performance with your Mark 4 IMS Base. The Leupold Integral Mounting Systems (IMS) raises the scope and pushes it forward, allowing this AR scope ring insert to to fit a number of scopes. The quick-release function allows for fast removal of the scope from mount for quick accuracy.