I used a reptile heating mat which overheated after a few months, blistering and causing the tank to get too hot for my gecko. The rep was very helpful, explaining how important it was to stick to the right size or the glass will not dissipate the heat, causing the problem. Although it was MY fault, she totally replaced my unit for FREE. I learned SO much User's recommendation: Love this company! I'll buy all my lizard products from them. Fabulous Customer Care!