I've got the original hard wired Atwood CO and Propane detectors. I see on Amazon I can get a CO for $65 (MTI Industries 65-541-WT 12-V Surface Mount Hard Wired Carbon Monoxide Alarm) and a propane for $53 (Atwood 36720 Hydro LPG Leak Detector). Sounds OK to me. What's everybody else doing for replacements? Thanks.<br/>jor