Our metric rims measure 17.5mm where they meet the cup and have Paxman Halstead-Chidell .800"-36 threads. They fit our metric cups as well as those from Halstead-Chidell. Our rims are available in five inner diameters in .5mm increments from 17-19mm. Other sizes are available as special orders. Our standard finish is gold plate. Gold is hypo-allergenic, non-tarnishing, and feels soft and slippery on the embouchure. Delrin rims are temperature neutral and work well for players who use a dry embouchure. Our plated finishes are very durable and, with normal care, can be expected to last for several years of heavy use. We can supply any of our rim contours in any diameter. To order a rim in a non-standard diameter email us at sales@osmun.com or call 978 823-0580.