This British Seagull part is suitable for Forty Plus, Century and Silver Century 10:35 reduction gear housings and Forty Plus and Silver Century 12:30 reduction gear housings including SJP, FP, GFP, EFPW, LS, LLS, W, S, WS, FPC, GFPC, EFPC, SEFPC, TSEFPC, WSC, ESC and QB Series Curlew & KC British Seagull Engines only.