Speaking from personal experience here.. the Reptitemp 500R "thermostat" is an awful product. PLEASE dont put your animal at risk by using it. the ONLY sutible environment (to me) to use it is one where your room temperatures dont fluctuate AT ALL.
the dial has no numbers on it! it is not a thermostat, it is more like a rheostat. i bought one when i got my girl last year thinking I could save some money. you have to watch it like a hawk. because the temperatures in my room were not stable at all the thermometer in her enclosure would read from 84 degrees F (on the hot side) to 114 F! I may has well not have tried at all with the thermostat!
I got myself a Johnson Control and am MUCH happier. Rich at reptile basics has fixed it for me, free of charge months after purchasing it when i had a problem with the power strip.
if your temps are stable in the place you have her in, then okay.. but personally I wouldn't risk it at all.