Magnetic Arrow
So simple and so effective, a wooden arrow with two N52 magnets glued in the rear so it will clamp onto any ferrous surface.
This one is black but they can be painted any colour to suit the GZ effect.
I do produce another style (QC 20) that uses a two part construction with the inner half screwing to a post etc and the outer lid section then clamping onto the mounting screws
A waterproof phial and log sheet are included.