AR-15 Carbine Buffer Tube
The AR-15 Carbine Buffer Tube is sometimes known as the receiver extension tube. This carbine buffer tube is what you need to install a carbine length collapsible stock onto your AR-15 style rifle.
The AR-15 receiver extension, also known as a buffer tube, is a mil-spec buffer tube manufactured in America. Most experienced AR15 shooters replace their commercial buffer tubes with mil-spec buffer tubes for a better lockup on their collapsible stocks.