Product Description Raypak Replacement Temperature Sensor IID Units for ALL Models. Raypak Item Code: 009577F Features Genuine Raypak Replacement Temperature Sensor for IID Units (3 Wire). Compatible with ALL Raypak and Rheem Aboveground Heaters: P-R156A-EN-C, and P-R156A-EP-C. Compatible with ALL Raypak and Rheem Electronic Ignition Heaters: P-R206A-EN-C, P-R206A-EP-C, P-R266A-EN-C, P-R266A-EP-C, P-R336A-EN-C, P-R336A-EP-C, P-R406A-EN-C, and P-R406A-EP-C. Compatible with ALL Raypak and Rheem Electronic Ignition Cupro Nickel Heaters: P-R206A-EN-X, P-R206A-EP-X, P-R266A-EN-X, P-R266A-EP-X, P-R336A-EN-X, P-R336A-EP-X, P-R406A-EN-X, and P-R406A-EP-X. Compatible with ALL Raypak and Rheem Low NOx Heaters: P-R207AL-EN-C, P-R266AL-EN-C, P-R336AL-EN-C, and P-R406AL-EN-C.