How can I determine the wires polarity?

Affected products

GT125-K2, TH1120-3000, TH1120-4000, TH1120P-3000, TH1120RF-3000, TH1120RF-4000, TH1121RF-3000, TH1121RF-4000, TH1123ZB, TH1123ZB-C4, TH1124ZB, TH1124ZB-C4

The TH1120, TH1121, TH1123 and TH1124 series thermostats have two non-polarized wires, meaning that either thermostat wires can be connected to either electrical box wires.