stainless steel shaft with ruby ball 2mm diameter to length 19mm and cra sh protection devices weak link length 12 mm with m4 threading to for op 30 cnc la thes in ams to part no a 5000 7547 and a 5004 7621 item description m4 sty d2r l19 ewl9 and m4 cpd l12slvs and m4 cpd l12slvs make renishaw or marposs or similar