Oregon 77-309-1 Spark Plug Replaces Bosch WS7F Champion CJ8Y NGK BPM6A Replaces KOHLER OEM # 24-083-03-S1, 24-883-03-S1 Fits 25 HP Command engine. Also M25 & CH18 6-7/8in OD x 5-1/2in ID x 2-7/8in H Use foam pre-cleaner # 30-945