If you have a 125T heater you need to carefully examine  your heater's existing ignitor to assure that you order the correct ignitor. A customer recently emailed and said that online docs showed 2 completely different ignitors being used in the 125T heaters.

Maybe this will clear up the confusion.

This document is from the DESA manual

 
 
The bottom line is:
  • If the nozzle adapter bracket has a square ignitor hole then use ignitor HA1000 ( PP200 new number)
  • If the nozzle adapter bracket has a round ignitor hole then use ignitor HA1100 ( PP201 new number)
HA1000 HA1100