Manufacturer of micro precision o-rings and miniature, custom rubber o-rings. The world’s smallest O-ring can be made as well as large o-rings with tiny cross sectional diameters. The smallest O-ring ID: 0.196mm C/S: 0.05mm no parting line in production and smaller by request. Our smallest O-ring developed and tested is ID: 0.05mm C/S: 0.05mm silicone, no parting line. Accuracy up to ID +/- 0.01mm C/S +/- 0.01mm. KEF can provide O-rings “flash free” and “no parting line” using our high mold technology. High quality medical O-ring such as: Medical in-plant, Wristwatch, Tooth brush switch seal, Optical and Microscope O-rings, etc.