Aimpoint
http://www.mountsplus.com/AR-15_Accessories/AR-15_Scope_Mounts/Aimpoint.html
Aimpoint Pro has been specially designed by Aimpoint to suit carbines used by law enforcement authorities, shotguns, rifles, and submachine guns. It is made of a 30 mm tube of hard anodized alloy to ensure durability and toughness to withstand all types of situations.