M-16 hammers, triggers, disconnector, selector, sear, lower parts kit, fire control group, pins, springs, and detents.

M-16 Parts to replace your used parts with new mil-spec parts.

Replacing AR-15 parts with some M-16 Parts does not make your rifle into a fully automatic rifle.  Also replacing AR-15 parts with M-16 parts, without legal paperwork will make your rifle illegal.  Please consult with ATF on how to obtain legal paperwork / documentation to own a fully automatic firearm. Possession of M16 parts in a rifle without proper paperwork can have legal ramifications such as fines, confiscation, and imprisonment.  Again, please check to make sure you have the proper paperwork to own or take possession of Automatic weapon parts before ordering.  Also be advised, taking possession or owning a lower receiver and having automatic weapon parts, may also have legal issues.  IE if you own a lower receiver, it is considered a firearm by law.