I don't know of any other places to get a voltmeter except madvapes.. the white one is usually in stock. You said something about getting one that worked with a drip well. If you buy a voltmeter from madvapes.. go ahead and get a 510 to 510 extender for it.. with a
device that has a drip well, the voltmeter connection is too short to screw all the way in.. a connector remedies this problem nicely. I have enjoyed my voltmeter.. it's a MUST for a vv pv that doesn't have a digital readout and it's also a good way to test that
device (with the digital readout) to see if the voltage it displays is the voltage you really get.
My madvapes voltmeter has been the best $15 I ever spent! I'd be lost without it! It's been very durable.. I've set something on top of it and the "male" connector kinda came out.. I pushed it back in and it works fine. I ended up using some gorilla glue to glue it in and it works great
edit: just checked the madvapes site.. both colors are out of stock. They should be more soon. They are worth waiting for.