Length of each collet: 1 & 3/4″; Max jaw opening 9-1/2″. Wide Application: The Valve Spring Installer Remover Compressor Tool Set fits for Most Car, Small Van, ATV, UTV and Motorcycle Engines. Function: The 10pcs Overhead Valve Spring Compressor Installer Remover Tool is used to compress valve springs or safely dispose of cylinder heads when removing and installing most cars, motorcycles or other small engines.