The Repti-Temp 500R is a dial-type thermostat that isn't worth the plastic its made of....

I used one way back when and when it broke, rather than shut off, it just ran the heat element it was supposed to control at full power....good thing I was home to see it before it got too hot in there....

For a RELIABLE entry-level thermostat, Ranco or Johnson Controls is the way to go. They are built like tanks and will last a long time.