This limit control is a universal replacement for many furnace models. The opening setting on temperature rise is adjustable from 135 to 175 degrees. The differential is fixed at 40 degrees and will close the switch when it cools back down to 40 degrees below the set point. These switches are commonly located in the airstream and shut the furnace down in the event of overheating. The face diameter of the sensing element is 7/8". The two holes in the mounting flange are 1-5/8" on center. This part is covered by the exclusive Protactor two year limited replacement policy. If this part fails within two years from date of purchase, return the defective part and a copy of the original invoice to the place of purchase for replacement. Contact the authorized Protactor dealer that you purchased the part from for details. Original equipment manufacturer's brand name(s) and part numbers are used for identification purposes only. This item is supplied by OneTrip Parts and meets or exceeds original equipment specifications.