Product review (1 stars): Beware of the part number - NOT a direct replacement for 3387134
This thermostat has only 2 contacts in the back.
The thermostat from my Whirlpool dryer has FOUR contacts.
The strange thing is both parts have the EXACT SAME part number....I don't get that.

I ordered this part for a whopping $17 (Amazon Prime) only to find out it has 2 contacts.
Had to return for the 2 contact version.

My understanding is that the extra 2 terminals are for an internal heater withing the thermostat to bias the temperature.
This seems to agree with the Amazon description of the 4-wire part having "internal bias" in the title.

Again - the big problem here is that both parts show the exact same part number according to Amazon.

So know which type you are trying to replace before ordering.

My one-star review is not based on the part working or not, but rather on the confusion that identical part numbers is causing.