Hey, yeah ... the comparison to an inter-galactic laser gun is what convinced me!
Seriously ... these are pretty good for very small jobs ... but they do take a while.
NAPA (Canada) sells the same thing in it's UltraPro tool line.
They actually have 2 versions:
Version 1: you buy the gravity-feed only gun, and then buy the capture kit as an add-on.
Version 2: Buy a convertable gravity/siphon gun which includes the capture stuff. And get this ... version 2 is very close to being the same price as version 1, so it's like getting the capture kit for free!
Obviously, I went with version 2 ... (P/N 65338) and I love it. If I have a considerable amount of blasting to do (without capturing), I'll fill a 5-gal pail with sand and blast away without have to stop to refill.
Switching between "modes" is very easy. Just flip a lever, remove or install the plug or siphon hose.
I've scanned the sheet that shows the kit contents / disassembly diagram. All literature is bi-lingual (English/French) as required in Canada, so I cropped the second page.
They don't seem to show the lever in the diagram, but I'm quite sure that it's on #23 "Conjunction" which must have been badly translated ... "Mixing chamber" is the term that I would have used ... which is a more literal translation as well.