Fits: Models with a Zama Carb as per list

Stihl

017, 018, 021
023, 025, MS170
MS180, MS210, MS230, MS250
Zama Carb

C1Q-S43, C1Q-S43A, C1Q-S43B
C1Q-S57, C1Q-S57A, C1Q-S137