The Dometic 9610008210 AC Cable Adapter Kit is used for upgrading the Penguin II to the new FreshJet 5 AC with Heat Pump. The RJ11 to RJ45 Adapter Harness converts existing RJ11 wiring (used with multi-zone CCC and CCC2 systems). For replacing with the new FreshJet 5 System an adapter is required when connecting an RJ-11 cable to a Connect Essential control board or CMC wall thermostat or when replacing a CCC2 10-button wall thermostat with a Connect Essential CMC thermostat. Required when connecting RJ11 cable to Connect Essential control board Required when replacing a CCC2 10-button wall thermostat with CMC thermostat | Dometic Air Conditioner Cable Adapter Kit for FreshJet 5 AC with Heat Pump