I used this relay as a replacement for my 3.5 ton air conditioner, the old relay is worn out, plug it in there and it works fine. I took off 1 star because the plastic is brittle. I broke one of the side panels around the screw clamp and I don't think I handled it too roughly although I worked like clockwork the first season, no problems so far ******* Update 30th September 2021 ***** My AC is blocked again so I figured the contactor had blown and there was probably something wrong with my AC that was causing this. I have since installed a micro-air soft start to help my generator with this. Anyway, I replaced and disassembled it and there was a lot of meat left on the contacts, but the return spring is not that good, I've been working for a year and a half, this time I bought another brand.