There fittings are 'prongs' approximately (they vary slightly) 3mm wide X 1.5mm thick, the outer edge is tapered, they are supplied by the manufacturer in the Far East.
There is an optional pair of fittings made by us out of hard steel, they are approximately (they vary slightly) 2mm wide X 1mm thick. We made these because we thought the original weren't the best quality or fine enough, and we recommend these for opening the rims of binoculars and telescopes.
Minimum diameter 15mm, maximum diameter 42mm.
Our returns policy (return any item you don't like, within 14 days) still applies, but if you return just some of a bulk order, and what you keep doesn't entitle you to the bulk discount, we will allow for this when issuing the refund / alternative items. Confused? - then please email first!
When returning bulk-discount items, if you request alternative items, postage is chargeable.