Attachment clamp mountings GN 478 are primarily designed for mounting sensor holders GN 479 and retaining plates GN 479.1. They are fitted with a central thread and, with d1 = B15 bore and higher, an additional bore template 4 x M4. The standard clamping screw is a socket cap screw with hexagonal socket DIN 912. It can be replaced by an adjustable clamping lever GN 511 (see table of dimensions).