Traxxas O-Ring Set TRX .12 For the TRX .12 Traxxas Engine Required Parts Carb for TRX .12 The O-rings are for the carb base and the needle valves 7 rubber O-rings of various sizes for the carb base, air filter adapter, high speed needle, and low speed spray bar HAS: 2 2.5mm o-rings, 2 4mm o-rings, 1 5.5mm o-ring, 1 1mm o-ring and 1 blue 3mm O-ring "