Digital Radius Gauge 3-in-1: Depth & Micrometer Tool | 0.5" Depth Measurement with 5 Interchangeable Jaws (10/20/30/60/100mm) | Radius Range 0.2"-27.5" (5-700mm) | Includes Calibration Plate

Great kit comes with every thing you need and is extremely accurate. Really handy for cnc work battery life with oem battery is not great I'm thinking mine was bad but easily replaced. The carry case is nice and has a secure lock so it doesn't fly open by mistake.

The media could not be loaded. This is a clever device that I was not aware existed. It's potentially useful to me to measure the curvature of guitar necks. (For those who don't know, the fretboard of a guitar is curved as if it were a section of a cylinder [or, less commonly, a cone], and how curved it is makes a big difference in playability. This curvature is described as "fretboard radius", and that's exactly what this device is intended to measure.)The problem is that measuring the radius of a curve using only a tiny fraction of its circumference means that tiny variations make a huge difference. For example, the measured difference, using the "claw" most appropriate for a fretboard, between a 7¼" fretboard and a 14" fretboard (probably the common extremes) is about 0.011". And a tilt of the indicator can vary the reading by 0.007".The provided (and replaceable) tip for the shaft should be the exact same shape as the tips of the claw. That would reduce the tilt variation significantly. But they're not, even though two additional tips were included.The flat bar that's intended to be used to set the zero point of the indicator has tool marks that are almost 0.001" deep. I suppose that's not significant, given the tilt variation, but it's sloppy.I noticed when I first touched the indicator that it didn't want to move away from being totally extended. It turns out that part of the internal mechanism that was attached with adhesive was left with the adhesive on uncovered sections, which then grabbed on to the frame. (Video attached.) Even better, the adhesive construction makes it essentially impossible to remove that part for cleaning. I was able to get in there with a cotton swab and some tweezers with the indicator still mostly assembled and get enough of the adhesive removed that it no longer sticks at the extent of travel. To be fair, since the working area of the indicator is with the shaft significantly depressed, stickiness at the end probably isn't a big deal. Then again, that adhesive might eventually get everywhere.That un-disassemblable nature is not great on its own, honestly. Also, one end of the spring retention is a screw that just has to be screwed in slightly without anything really tensioning it. Very cheap, sloppy design all around.And one of the claws had so much flash inside that the shaft wouldn't fit through it. Fortunately, I had a narrow scraping/deburring blade, but without that, that claw might have been rendered unusable.On the other hand, the unremovable part with the adhesive was the grating that the indicator measures for distance, and it is made of glass, which is an oddly high quality choice given the apparent quality of the rest of the design and construction.All that said, it basically does what it says it does. It gets close enough to accurate for my purposes. I don't think I could ever rely on it for real measurements, but when it tells me that a fretboard is 7.4" in radius, I can feel certain that it's 7¼". And when it says 9.6", I can feel reasonably confident that it's actually 9½".

The media could not be loaded. Does not measure correctly, is unacurate