Thermapen all the way..As Bar-B-Lew said check w/ Thermoworks.. They repaired my classic 'pen and it works 100%..I also have a mk4. So much better;Waterproof,automatic light,battery cost ~ a tenth the cost and using 1 "aaa" cell that last 2x longer than
the two button cells of the classic, auto on in sleep mode, adjustable sleep duration vs one set time. I think that is it..Have fun!