This is the oil-thermostat used in the 'early 2.0' liter 911S engines. The 911S oil-thermostat unit did not have a mounting-bracket incorporated in the backside of the thermostat body since it was not necessary. Look here at a photo showing the back of the 911S thermostat http://www.pbase.com/9146gt/image/31600930 and here to see the front side http://www.pbase.com/9146gt/image/31600929.