Opens clogged grease fittings and loosens hardened grease joints. Excellent for maintaining and protecting bearings, control arms, joints, king pins, etc. Tool has an all steel construction & is designed to be tapped with a hammer to force a light viscosity oil through the tool into the coupler & finally into the grease joint, breaking up and removing dirt and debris. Built-In Hand Guard for added safety in use. Flexible hose attachment reaches fittings in difficult areas.