Specification: KN series 4 holes 10 teeth Material: main part 45# Steel, worm & worm wheel: ... Certification:ISO9001:2008Reference number:KN47001, KN44051, 18-048, BPW 6 Holes, Benz,BENDIX, etcMaterial: mainpart:#45 worm & worm wheel: 40CrColor: yellow ...