The DTL U-Shield Tactical Scope Protector - Type 5.  This is a 3" high x 2 1/4" wide lens protector. The clear high quality acrylic lens to protect your valuable scope/sight from damage. Unlike lexan and other polycarb systems, this is acrylic, which offers superior "clear" vision through its lens.  Very impressive!  Mounts on all rails. To install, simply slide the metal mount down your rail, insert lens, and tighten with included Allen key tool.  

The Type 5 mount is great for larger scopes and sights, like cantilever, high rise, and ACOG style.  The Type 5 is quite tall.  Use a riser mount in conjunction with the DTL U-Shield to make it QD (quick-detach) and to rise up to certain sights' heights.