This is the PK1 M8 to M8 knuckle joint #A-1014-1720. The PK1 provides non-repeatable A-axis and B-axis indexing. It can be used on any M8 threaded head.
Renishaw A-1014-1720 PK1 M8 to M8 knuckle joint
A-1014-1720 | PK1 M8 to M8 knuckle joint | Knuckle Joint | Machine Probes: Extensions | Renishaw