Spring loaded design. One of the strongest closed cam type of rope-grab ascenders. Round tooth cam design minimizes rope wear yet holds on wet or icy ropes. Spring attachment increases cam's range of motion to decrease chance of spring breakage. The 1/2" model attaches to synthetic ropes 5/16" to 1/2", the 3/4" version accommodates synthetic ropes from 5/8" to 3/4". The spring-loaded type is always in locked position and is recommended for general rescue use. Forged cam, 5200 lbf, general duty.