Hi shifty,
It's the powder flask I started with and normally the only one I use. I believe I can load around eight or ten 90gr. full power loads from this flask before it needs refilled. I knew precisely at one time, but the memory has faded. During a normal range session, I usually have to refill it once.
It has a short fixed spout below the valve that is not meant for measuring so you should bring along something to use as a powder measure. The spout may hold something in the neighborhood of 10 to 15 grains, so it might be useful for measuring a load for a .32. On the other hand the spout is big enough that it would be hard to direct the powder into a small bore. Like I said, it's not meant for measuring.
The valve is a brass cylinder with a hole in it that is opened against a coil spring by pushing it sideways with finger pressure. Spring pressure closes the valve.
Only hangup I've ever experienced with mine is that corrosion will build up on the brass cylinder between shooting sessions and, if bad enough, may restrict cylinder movement. This usually means you can open the valve with the fingers, but the spring won't close it. You can, however, force it closed using finger pressure on the backside. Best approach before filling is to work it back and forth a few times with the fingers until it loosens up. The valve works fine if you remember to do that.
The brass, screw-on top has a plastic capplug in the middle. I suspect this is for blowout protection.
I like mine and it's held up for about 8 or 9 years now without difficulty
Bob