The BG972HAK P1 is a high altitude conversion kit for BG972 models that are field converted to use propane. It is works with all 70000 input btu models of those series. It includes all needed parts for the following application.

It is designed for high altitude, propane (LP) applications ranging from 4501-7500 feet above sea level.

This kit includes: 

14a48 (Switch-Pressure .85/.50 WC) 2 stage high altitude pressure switch 

BG11K48 2 stage propane conversion kit (low pressure switches are included with all Blueridge LP conversion kits for additional piece of mind and to protect your investment)