Konohan 2 Pcs Brass Pocket Caliper Double Scale Mini Tool for Jewelry | Vernier Gauge with Dual Scales, Metal Calipers for Beads Wire Rings, Portable Mini Ruler Measuring Jewels Sizing Crafts

Good enough build quality and accuracy. They are not perfect precision instruments, but neither are they meant to be. Most useful for a quick measurement on a nut/bolt head or a shank or hole. They do not lock in any position, so some dexterity is needed. All said I would recommend adding something like this (yes, there are other similar options) to every toolkit.

Great, small measuring device

Compact slide to measure bolts or nuts. Should last a while since it's all metal

I don't do meticulous work, but it's good to have a pretty accurate measurement in my work. These work great, require no batteries, slide easily and are as good as your eyesight is able to discern parts of a millimeter!

Work great, and great value! It does take siding them back and forth for a few minutes when you first get them to clear out the track from some debris, but then they are smooth as can be. Reading isn’t an issue, and they seem to be accurate when compared with the others in this pack. My only complaint is that there is no indication for inside/outside measurement reference offset, but it’s measured at 5mm and is consistent among all 4 I received. Overall, great value.

Good value for the money. Some what loose build quality. Slides easy and good size. Looks nice but don't know if inwould buy again

Good for quick outside diameter measurements, easy to read.Less helpful for inside measurements, it’s hard to read because there’s no reference markings inside readings.Still, it compact and handy.

Reach for one of these often - I've not developed a reliable eye for judging bead size yet, especially when there are two sizes of the same type/style of bead.