"Precision swivel ball that can be used either as a contact bolt or as a rest pad. As contact bolts, these swivel-ball units are ideal for evenly distributing clamping pressure on sloped or uneven surfaces. The bolt is manufactured from S45C(JIS) \/ CK45 (DIN) heat treated to HRC 35 and the ball is manufactured from SUJ2(JIS) \/ 110Cr6(DIN) heat treated to HRC 62. The surface finish is black oxide."