To add to my install I did go with the harman adapter from the pellet vent pro line. I'm hoping it is not only made to fit the harman outlet better but also is a little longer. If you go from the appliance adapter directly to a tee or elbow with a stand appliance adapter on a p61 you find yourself right at the minimum 1 inch air gap to the hopper. If the harman adapter is a little longer I would feel much better