You have two choices of base model, one with power cord that's permanently attached and another one that's detached.

Choose permanently attached base unit where the access is convenient.

Otherwise, choose another one when power inlet is accessible.

Choose power you need, 110 volts at 60Hz or 230 volts at 50Hz.

Choose one of two fittings available.

1. 19mm
2. Male #8 A.N. JIC

There are two thermostat range.

1. Will reach and hold 55 degrees Celsius or 130 degrees Fahrenheit (Two cycle application)
2. Will reach and hold 80 degrees Celsius or 175 degrees Fahrenheit (Four cycle application)

Choose your mounting options.

There are two thermostat housing - S and R.