This is a synchronizing link for your carbs designed to be strong and originally for my 1972 Honda CB350F. Would probably fit other models, but I don't have any other models to test them on. 4into1 says they fit the '75-'77 CB400F, '71-'73 CB500K, '75-'77 CB550, and '74-'76 CB550K. Print them with a high-temp material; I used ASA. They won't need to be mirrored or anything, just print as many as you need. When installing: the notch faces the linkages to allow clearance. Honda part# 16029-323-004.