Fits Mr. Heater: MHU45, MHU50 ,MHU55, MHU75, MHU80, MHU85 Heatstar: HSU45, HHU50, HSU55, HSU75, HSU80, HSU85 ProCom: GHBVN50, GHBVN80, GHBVL50, GHBVL80 Replaces part #60015 Easy to Replace Alternative Part Numbers: KSD301-080 Manufactured by OEM. Heat Exchanger High Limit Switch for MR Heater, Procom, and Heatstar furnaces. - This is a commonly failed part if you are receiving 4 flashes on your Mr. Heater unit. It's likely either this high limit switch, or flame rollout switch. These are Normally Closed switches and will opens on a High Temperature or Over temperature rise. - Compatible with the following and many more models: Mr. Heater: MHU45 MHU50 MHU55 MHU75 MHU80 MHU85 Heatstar: HSU45 HHU50 HSU55 HSU75 HSU80 HSU85 ProCom: GHBVN50 GHBVN80 GHBVL50 GHBVL80 - Alternative Part Numbers: KSD301-080