The standard Hatco Heated Wells are generally top mount Heated Wells and they simply drop into a hole (cut out) from the top. Full-size standard Heated Wells (HWB-FUL) can also be mounted from the bottom by using fasteners in the side walls of the well. Full-size Heated Wells are also available in insulated versions that can be top mounted (HWBI-FUL) or bottom mounted (HWBIB-FUL) in a similar fashion.