The Herpstats by spyder robotics are Equivalent, if not better than the Helix. That is just my opinion, so check it out for yourself, go to reptilebasics.com, they have thermostats as well.
We use these for our large rack, baby rack and T3.
I rack my husbands balls & show my rack on Ball-Pythons.net ~I make girls with balls look good~
Qiksilver "yes, watch your children, I'll convert them to satanism..."