Quick change cylinders from Tooling Technology replace traditional nuts and bolts. The Segen quick change devices consist of a steel cylinder lock and a corresponding knob. The cylinder lock, designed to receive and mate with a conical male knob, locates and positions the knob to within 0.0002 in with a holding force of up to 25,000 lb per device, depending on cylinder specifications. Positively locked in a static state, the cylinder lock actuates when air pressure is applied to release or receive the knob. The cylinder locks stay mechanically locked until pneumatic pressure is applied to release them automatically. This ensures a secure, fail-safe hold, even if pneumatic pressure is lost.