The Model I-300 spring-engaged, air-released, power-off brake provides high torque for backlash-free holding and emergency stopping on indexers and positioning systems. The brake’s high torque and short response time help to ensure the shortest possible stopping distance. The brake connects to the shaft with tapered, keyless locking devices. It is normally engaged until air pressure is applied to release it. A patented braking element locks and holds the shaft in position without any displacement upon engagement or reversing of the load. The product is stackable for double the braking torque and is horizontal- or vertical-mounting.