In-line tool oiler, compact, fastens directly to the air tool, precisely meters proper amount of oil to the tool only when the tool is in use, use on all air impact guns, air wrenches, body shop air tools & pneumatic hammers requiring 1/4" air lines, no adjustments necessary, 1/4" male npt outlet, 1/4" female npt inlet, never use motor oil in pneumatic tool, prevents burn out of expensive pneumatic tools stops, rust & increases torque up to 25 percent.