Jelco Easy VTA on the Fly

Saw these on ebay $76.https://www.ebay.com/itm/jelco-VTA-for-sa-370-750-ts-550-sumiko-mmt-tonearms-turntable/153153455630?...

https://www.ebay.com/itm/low-profile-jelco-VTA-for-sa-370-750-ts-550-sumiko-mmt-tonearms-turntable/1...

@lewm in fairness, it's something that is useful and an extremely niche, enthusiast product. 
@gary7  these are cheap knock-offs of the OP's product, which looks and apparently is a more highly engineered device.

Some more nice pictures of the new Improved version.

https://www.analog-forum.de/wbboard/index.php?thread/134608-jelco-easy-vta-on-the-fly/&pageNo=22

This is a very interesting product.  Would it fit on a Pro-Ject tonearm mount? Cheers,

Hello

If the Jelco has a 18mm shaft, then it will fit just fine.

In the meantime, nice review from The Ear Magazine.

http://www.the-ear.net/features/vta-made-easy