A guide used to drill 3mm Arri anti-twist holes in existing plates and fixtures. Wse two screws to index and lock the guide in place and use a 3.1mm drill bit.

One of the ¼-20 holes is for the ¼-20 spec with is 10.4mm spacing. The other shares the 15mm spacing for 3/8-16 spec.

0.2 or 0.4mm nozzle is preferred due to thin wall of the ¼-20 hole with the closers spacing for ¼-20 spec.