This only works if the board has leafield valves. I believe that includes NRS and JPW.
There is a spring in the adapter that pushes the poppet open, and that allows you to take air pressure readings with a tire gauge, and fill it up the rest of the way at the gas station.
Here at jpw we do not recommend inflating a 6 inch board past 20 lb., and 16 will give you plenty of stiffness. Btw we did a destruction test years ago, and it was 53 psi when it exploded and it did not ruin the drop stitch, but blew a rip in the side wall, and not on a seam either.