DOP30660ST066 Stihl 066 Oil Seal Set No. 9640-003-1850. This is a quality aftermarket oil seal set that fits later style 066 chainsaws with the poly flywheel. Does not fit the older 066 or 064 Chainsaws. Replaces stihl chainsaw part numbers 9640-003-1560 (9640 003 1560 and 96400031560) and 9460-003-1850 (9640 003 1850 and 96400031850.)