This is the complete, optional Remote Needle valve assembly for the O.S.21RZ-M engine. Features: -Sturdy -L- shaped needle mount w/nut -Aluminum inlet nipple. -Steel Needle holder with outlet nipple on other end. -Standard .21RZ-M Needle #OSMG7025 -Sturdy aluminum control horn. This horn looks like a servo horn with two arms at a 90Deg offset. This horn locks on the needle with a set screw, and allowes Needle adjustments with a servo. -A chromed brass threaded plug w/gasket. Includes: 1 -L- shaped Needle mount ///// 2 round gaskets (1 paper-1alum.) 1 aluminum fuel nipple ///// 2 steel nuts 1 aluminum control horn ///// 2 1.5mm set screws 1 Needle holder/nipple ///// 1 needle -O- ring. 1 ratchet spring 1 Threaded plug Comments: O.S. has made this an optional part for the O.S. 21RZ-M engine, but this part will also work with several .O.S. engines. This will fit most O.S engines that have the FUEL INLET NIPPLE MOUNTED ON THE CARB BODY.