I bought this to control my bearded dragon's basking spot temps. I use a reptitemp 500r for my other lizard, and it works great, but it is a bit more expensive, so I bought this hoping to get almost the same results. This is the worst rheostat. I plugged it into a clamp lamp rated for 150 watts, and within a week the rheostat dial melted. Most reptile lamps need to be approved for 150 watts or more, and I had a 100 watt bulb plugged in. This rheostat should not have malfunctioned. Pay a bit more and get a better rheostat or, just go to home depot and get a dimmer.