Strip therm is one of the 4. No probes, they are remote units, so they are little boxes that transmit temp and hum readings to the base unit. "cordless". Hopefully that is OK they were not cheap, but not super spendy either.

UTH is (for now) the smallest and not a 40 gal tank heater. I did this because I have lights. I may switch to the 55W infrared full time. The snake has not used a hide yet. She continues to sit on a branch under the light. The UTH in not regulated at this time. If I put the back of my hand on the glass where its mounted (yes outside tank) it's warm but not hot.

Before our summer trip I may switch things up yet again and get the full sized UTH and the thermostat, or if humidity probs don't resolve afetr a few attempts here and a weather change.

So, 1 remote is on top of UTH and under the light. (the humidity one)

The other is on the cool side. Both on the floor of tank.

The other 2 cheap ones are center tank just off the floor and cool side 4-5 inches up back glass.

If needed I'll switch humidity unit to cool side if you think that is best.