This unique, 1144 stress-proof steel cleaning tool lets you easily clean clogged grease joints or fittings to take on new grease. The process is simple: Remove the piston from the tool body and fill with a light viscosity oil (such as penetrating oil), bleed off any air and place the tool onto the fitting. Then, tap the piston head with a light hammer until the piston moves down the tool body (which tells you the clog has come free). NOTE: This grease joint cleaner comes in a black blow-molded case.