I just picked this one (or one very similar) recently and I love it. It has replaced the vol-con on my tool bags.
They're probably not unique products. Techtronic industries of Korea owns Ryobi, Ridgid, Milwaukie among other brands in N.A. market and its probably just made by one of the manufacturing companies in China and just have badged to specs.
As for stray voltage, you can get a Fluke SV225 3kohm resistor pack. It still retains meters' CAT III 1kV and CAT IV 600v safety specs. Those wiggies do not stand up to these safety specs.