Model# 18021 works on FS6,C171,6p148,GM R4,A6,HR-6,DA-6,V5,and SANDEN SD-505,507,508,510,575,708,709. We dont replacem at the dealer everybody gets a compressor (LOL) so they dont get much use in my box. They,re in excellent condition in original case. 50.00 t... Login to read more.