Each multivibrator features both a negative, A, and a positive, B, transition triggered input, either of which can be used as an inhibit. Also included is a clear inpt that when taken low resets the one shot. The HD74HC221 can be triggered on the positive transition of teh clear while A is held low and B is held high. This device is a non-retriggerable, and therefore cannot be retriggered until the output pulse times out.