The BDTM932 is specifically designed to be mounted under a differential p... The BDTM932 is exclusively made to be mounted below a differential pressure gauge. This gauge provides a G1/2A connection with a normal 54mm hart to tough distance. The FP variety calculation just isn't proper / obvious to me https://erickowdlr.bloggactif.com/17964506/how-much-you-need-to-expect-you-ll-pay-for-a-good-diaphragm-seal-pressure-gauge-wika