GemOro 18K Calibration Disc | Accurate Compact Yellow Gold Disc for KEE, Auracle AGT1, AGT2, AGT3, Auracle Analyzer and Auracle PRO | Precision Tool with Expert Professional Reading & Accuracy (6.4mm)

Expensive little piece of gold, but pretty much required to calibrate Key gold tester.

It's fine

A tiny piece

You need this calibration disk if you havevthe actual unit

It’s the size of a popcorn seed, I could buy 800 of these for $24 lol! They zoomed in on it to try to impress the chicks and make it looks way bigger than it is…

I wasn’t expecting anything large and it wasn’t. The disc measured 7mm in diameter and 0.44mm thick. It is 18kt yellow gold with a high polish finish.My piece weighs 0.13dwt or 0.202g. It works very well. As others have noted it is very small and easy to lose. I have mine sitting on a gray background so it’s easy to locate. It can be easily picked up and placed with a pair of tweezers.

This is so tiny, it came in a very small zip baggie in a very tiny envelope and almost went in the trash. It was in a box with other items from Amazon and was stuck in the bottom fold of the box. I had to search boxes I threw away and found it. It’s a good product but could you put it in better packaging please. Thank you.

Other than being tiny it's the focal point for calibrating the gold checker got to have it or something exactly like it