The T91 has a 4-position selector switch: S – safe, 1 – semi-automatic, 3 – three-round burst, and A – automatic. Like the T65K2, the T91 utilises an M16A2-style front post, rear peephole sight. The rear sight, mounted on the detachable handle, is adjustable for windage and elevation. Operation of the charging handle, magazine release, and bolt release are the same as the M16. One notable difference is that the T91 does not have a forward assist, and the brass deflector is not as pronounced.