Low voltage control of gas or oil heating and cooling equipment. Bimetal temperature sensor. Snap acting switch (magnetic switch) does not require leveling and is mercury-free. Simple, worry-free operation. Dual temperature scale F deg./C deg.. Decorative backplate included. No. CT30A1005/E1: Temperature Range: Heat Only, Pkg Qty: 1, Package Type: Clamshell No. CT31A1003/E1: Temperature Range: Heat or Cool, Pkg Qty: 1, Package Type: Clamshell