I installed a thermometer in my Igloo 10 gallon MLT and I am iffy about it leaking. Being a software guy, I don't consider something done until it's been verified, so it's killing me that if it's leaking, it's doing so into the insulation and will essentially never be discovered. I probably wouldn't be worried about it but I think I cut the hole just a hair big. Not much, but enough that I'm not convinced I'm getting 100% compression on the gasket where it needs it. Maybe 90%, maybe 95%. The problem is I don't know. Comfort me.