If you purchase a standard Brew Bucket it does not have provision for a thermowell. You can just buy an adhesive strip thermometer and they work great on stainless because stainless is a way better conductor of temperatures than the plastic buckets that these historically have been stuck on the most in entry level HB kits.
If you want to upgrade a bit and have a Bucket with a thermowell, we sell those to under the model name "Brewmaster Bucket" CLICK HERE to check it out.
This includes a thermowell and a very nice LCD temperature gauge in the box standard.
An elegant solution for not that much more money on the upgrade.