Thomas Service Kit. Kit includes Cylinder orings, connector tube orings, head gasket, foam filter, top end screws, Loctite®, valves, valve keepers, valve screws, valve restraint, .22" stroke connecting rod assembly. Kit is compatible with standard Thomas 2617, 2627, 2637 (22 Stroke), 2618, 2628, 2638 (22 Stroke) models (This item currently has a tariff surcharge which will be added to your order as a separate line item. Tariff surcharges are subject to change.)