I use a Sovereign fermenter which is very similar to an Anvil. I bought a thermowell with a two hole stopper. The thermowell two hole stopper was a little small so I made a sleeve for it by cutting the small end off of a universal stopper. The two hole thermowell stopper fits inside of the modified universal stopper and the entire assembly is inserted into the hole in the fermenter cover. Cheap, no leaks, no modifications to the fermenter, and it comes apart for easy cleaning. Hope this helps.