Both of MotoPressor Pocket Pump and Mini Pump have a screw-on chuck. For the "Dextrously Challenged" and "Fat Fingered" few, it can be a little challenging unscrewing the chuck without losing 1-2 PSI. So, here's a solution.
The MotoPressor Clip-on Valve Extension with deflation button, screws into the end of the inflation hose on either pump and turns it into a clip-on/clip-off chuck. There's also a deflation button built into it, so you can release air if you over-inflate.