Ring size selection: Circular ring and arc ring: 40mm/45mm/50mm the length of the cage is 20mm, and Cage the inner diameter is 32mm. The material of the product is stainless steel, smooth surface, high-tech production, please choose the right size to avoid size inconsistency Important: product dimension tolerance does exist, due to the below 3 reasons and this tolerance (±1cm) generally is considered to be allowed. Please do NOT make the purchase if it is not acceptable for you. ![]() ![]() ![]() |