Diver underwater GPS/VHF, Nautilus Mark 1

Nautilus makes underwater GPS/VHF for diver safety, so that if you surface and the dive boat is missing, you can use the GPS to determine your position, and the VHF to radio any boats for a rescue.

These are the old, Mark 1 units, although I have just replaced the internal batteries, and they should last as long when transmitting, as when they were new.

However, the Nautilus company is offering a huge trade-in discount of old sets, in any condition, on a new set. Check out their website.
So if you were thinking of buying a new Nautilus anyway, these old models will actually cost you less than nothing, considering the trade-in value.

Reason for sale - I'm giving up diving and boating.

Price is for each set, not both.