One of those cheap-arse Chinese vacuum hold-down pivoting vices.
I'd never bought one before, due to my workbenches usually being wood-topped. Which are too rough and porous to hold a suction cap seal. But now my soldering desk has a mirror finish ceramic tile top, which works as well as glass with the suction cap.
Recently I looked these up on ebay-from-China, and found prices of Au$31 (free post), or Au$20+$12.50 postage. I'd intended to buy one the next time I ordered some stuff.
Yesterday I happened to be in Jaycar Bankstown, and their price for the exact same model is Au$29.95. Ha ha... I wonder what their import landed price was?
Anyway, it's one of those simple, cheap but never-quite-happened things I've wanted for most of my life.
They are cheap diecast, wouldn't do for any rough work, but are great for holding circuit boards while soldering. The jaws are steel, with V-grooves and rubber clip-on soft-jaws.
By the way, those tiles are 600mm square, hard vitreous stoneware ceramic, and come in 3-packs for about $12 a pack from Bunnings. I happened to also have a few half width ones in a different color I'd found in a dumpster ages ago. Together they fit the table very well.