Compatibility: This product is compatible with Stihl BG 55, BG 65, BG 85, SH 55, SH 55 C, SH 85, SH 85 C, HS 81 R, HS 81 T, and HS 86 R. Compatible with Zama C1Q-S68 models A through D, C1Q-S105, C1Q-S111, C1Q-S115 (including variants A and B), and C1Q-S116 (including variant A). Product function: Prevent air leakage: Ensure a tight connection between the carburetor and the engine intake manifold to prevent air or mixture leakage and affect the air-fuel ratio. Maintain vacuum: The engine needs a stable vacuum environment to operate normally. Poor gasket sealing can cause vacuum leakage, causing problems such as unstable idle speed and power reduction. Prevent icing: In cold environments, direct metal contact may cause carburetor icing. Gaskets can reduce heat conduction and reduce the risk of icing. Product include a total of 2Set Carburetor Diaphragm Kit, which can completely meet your daily use needs and replacement., Manufacturer: OTOTEC