Simple Compass in a nice rubber housing.
Points north, allowing the diver to swim the exact opposite way from the skippers’ instruction.
All the usual features including lubber-line, bezel and side-view window.
In-built compasses have a habit of getting smashed on the dive-boat, which goes unnoticed until it’s needed. This is separate, so can be stowed safe until needed.
Works perfect with a Loop Shock Line allowing for a bit of distance between it and other electronic devices – i find that LED torches always screw with magnetic feilds.