Note: The coupling is double joint, and has pin gap and clamp spring groove."10x20x67.5mm" means its inside diameter is 10mm, outer diameter is 20mm and size is 67.5mm.For a wide range of general-purpose equipment occasionEach part of extreme rotation perspective of 30 °Material: 40CrMo Alloy SteelSurface Treatment: Blackening or PolishingSeiko Quality, Fine Workmanship, Dimensional AccuracyOver-compact honing, precision fit, sturdy wear resistanceMaximum articulation attitude is 30Size"Inner Diameter(d) * Outer Diameter(D) * Length(L2):6x12x49.5mm,8x16x58mm,10x20x67.5mm,12x23x83mm,14x25x94.5mm,16x32x117mm,20x36x139mm(if you would like different size, please ship us a message)Package Included:Universal Joint x 1