The Nokta pointer is only waterproof to 1m.
My experience is with Minelab Pro Find 25, and Vibra Probe 580.
Here are my reviews:
(out of 5 stars)
The Minelab is excellent 
Range: 20cm
Sensitivity: Just under 5mm cube. Adjustable but I kept it on max at all times, so didn’t really see the purpose of having the adjustment.
Battery: 9v Ages
Yes (apparently can be switched off for nighthawking 
)
Beep: Yes
Vibrator: Yes
Water: Water resistant. Can be made waterproof to 10m
Auto off: Yes after 8min
Vibra Probe 580
Range: 12cm
Sensitivity: Just under 5mm cube
Battery: 9v So far, it seems to be ages.
Light: No
Beep: No
Vibrator: Yes
Water: Waterproof to 10m
Auto off: Yes after 1min, very annoying, too short.
Comments: On/Off is by tilting to vertical, this is annoying as it will turn on or off when you don’t want it to. Probe tip is quite long at 14.5cm.
I’ve heard the Garret Pro Pointer AT is excellent. Also waterproof to 3m.
It has a ruler on the side, and strap loop clip.
I’m experimenting with making my own pointer, and I’ll definitely ensure it detects 100-200g gold pieces.