I'll put in my vote for a proportional thermostat as well. I have a Helix that's on my quarantine rack; they're okay if you want to pinch pennies but if you're going to be into snakes for the long-haul, you can't go wrong with the Herpstats from Spyder Robotics. I have a Herpstat II ND on my collection racks and love it. No thermostat is going to be able to heat appropriately using just the Flexwatt without supplemental heat in the room, so keep that in mind if you're looking for one that's going to do it all. So long as your snake room or wherever you keep your animals has a stable temp, most any quality proportional thermostat will do the job for you and with most of them, you get what you pay for. The Herpstats have a nice feature on their web-site where you can compare features of the various models to find the one that works best for what you need, if you elect to go that route.