The 3 1/2” - 8 UNC Threaded Ring is a direct replacement for the original rings, provided with many portable CMM's, standard surveying equipment and optical alignment instruments.

It has been turned from stainless steel and comes complete with 6 x 10-32 UNF screws, 6 x M5 screws and the corresponding hex keys.


Designed, manufactured and tested in the UK.

Terms: 
Paypal, card over the phone, bank transfer and other cleared funds are all accepted.
We ship worldwide every from the UK everyday. Most items will arrive within 1 week as long as they are not held up in customs. 
We can’t be responsible for any import duty so please check before purchasing. Commodity code 9031:90:00 (Accessories for CMM’s is zero rated in many countries however.) 
If there are any problems with your order, please do not hesitate to contact us. We will do our best to sort them out.
For UK orders please use the UK site.