For OPTIMYST INSET BRASS(RTOPI20BR). for OPTIMYST WALL FIRE for FSC(RTOPW20). For Electric Fire Brushless Fan Motor Unit. CASSETTE 400 HEAT LARGE LOGS(CAS400HLL), CASSETTE 400 NO HEAT LARGE LOG(CAS400NHLL), CASSETTE 600 HEAT(CAS600), CASSETTE 600 NO HEAT(CAS600NH).