The product is a set of 3.1mm cross section O-rings made of nitrile rubber (NBR) with a 36mm outer diameter and 29.8mm inner diameter. These black O-rings are oil resistant and manufactured in China by the brand OTHMRO. The set includes 10 units and is designed for industrial automation and motion control applications, particularly in the field of mechanical power transmission. These high-quality O-rings provide reliable sealing solutions for various mechanical systems.