Clement tire gauges were the THING to have back when I was racing. I was able to borrow one. I made one myself from a automotive compression gauge, a Campagnolo head, some borrowed silver and a torch.
They were unobtainium in 1974. A 60's -very early 70's thing. Note, inside the head is a little machined cylinder that floated around, it depressed the valve stem to open the tubular valve and read the pressure.
This is the time when Hite pumps ruled the velodrome.
And one pumped your clement #1's or #3's to 10.5 atm.