Solid construction, design could be just a bit better - Magpul Industries AR-15 Armorer's Wrench Accessory with Bottle Opener

This wrench is forged from think, high quality steel. It includes hardware for torquing down all the major parts of an AR--the barrel nut, the castle nut, the flash hider and muzzle device. The recommended torque values for all of these are roll-marked onto the handle as well, which is a nice touch. I can't quite give the wrench five stars because of compatability issues, however. The closed loop of the castle nut wrench means it isn't compatible with certain kinds of receiver extensions; the standard buffer tubes will work fine, but if your extension is thicker than normal (such as pistol buffer tubes), or has an integrated stock or similar protrusion, you won't be able to use this wrench.