Complete kit to service your Fleece Performance Coolant Bypass Includes all O rings, fasteners, and a new thermostat. Two thermostats included to service all production years, you will only use one 1 of the included thermostats when replacing your bypass thermostat. This kit does not include the Cummins thermostat. The kit includes 3 new square cut O rings and 1 new standard O ring as well as 2 new O rings for each of AN fittings. When used with MY94 MY2002 kits, not all O rings will be utilized.