There are better ones out there, but the one I have cost 30 euro off Amazon and it has survived mor than a year of abuse and still going strong. GP Pointer its called. Maybe try Amazon.de to avoid brit tax!
It is not completely waterproof, but from the on/off button to the end is waterproof.
I had 2 gp pointers. Great piece of kit. I drowned the two of them by tryin to use them under water....the vibrating thing that spins around can stick, but you can buy 4 gp pointers for one Garrett carrot....if you can afford it..get the carrot. Probably last longer, with better sensability