The gauge works great and is very accurate. I am a technician for Universal Toyota so I use this tool on a daily basis and the spare battery will come in handy.
I purchased this tire gauge to measure the depth of an astro camera sensor. I checked the accuracy of this gauge against a .5 millimeter a 1 millimeter extension ring. It seems to be accurate within a 10th of a millimeter. I'm very happy with the way this cage performs.
Using it to track the depth on my Tesla Model 3 to judge when to rotate the tires and to check for uneven wear. Very accurate and super easy to use.
Matches my caliper exactly. Easy to read and interpret make sure to turn off after use or have lots of batteries.