This is the Pipe Vise Micro 5 (model SW127-14), a small self-adjusting wrench that can be used on fasteners, toilet bolts, supply lines, smaller tubing and pipes, or other such materials.
It works in a similar manner to the brand’s excellent portable pipe vises and larger wrenches, but in a size that takes up little space in your pocket or tool bag.
The Micro 5 is 6″ (152mm) long and can fit fasteners or cylindrical stock from 8mm (~5/16″) to 14mm (~9/16″) in diameter. It weighs just 0.28 lbs (130g).
The wrench features a self-adjusting and ratcheting-action mechanism, comfort contoured handle, and durable chrome finish. It looks to fit well in tight spaces.
Price: $55 with free shipping (USA)
Keep in mind that the jaws have serrations; the tool shouldn’t be used on delicate fasteners or fittings.