The heat may I be got is about 10 mm smaller it's a Komodo 14 w I think you get about 5 mm a ll the way round. The best tape I ve found is electrical insulation tape. If the mats to big I wouldn't know how to stick it I guess it would keep coming off. I found when mine were that small they didn't like that size tank much. I used the nano cube for them. Got two at the moment with them in temps all fine. It's experimenting really ceramic/infra red heaters are what I want to use really with heat mats for back up.