I bought an immersion circulator on ebay that worked perfectly. The seller had a ten day return policy. Unfortuately, the wire that attached to the temp. probe shorted out (I didn't know it shouldn't get wet) and the repair costs exceed the price I paid on ebay. I just bought another immersion heater (after getting confirmation from the seller that I could send it back if it didn't hold its temp.). Hopefully it will work as well as the first one -- and last longer than a few weeks!