I'm sure any marine or boat store would have the product. I must admit that most of my loot comes from knee to chest deep. I do like hunting the low tides, as it is easier to get to the deep water without getting beat up. I will hunt in high tides if necessary though. I ain't skeerd! The shallow water gets more pressure and the lighter weight junk seems to hang there more often, unless of course you are at VA beach. In my area, I would have to argue that the loot is deeper. Just watch the people in the water. They are wearing rings, chains etc. They loose it out there and have NO IDEA where it is. The gold burrows itself in the sand and despite their futile efforts it will not be found until you sweep over it with the unit. I'm not saying you will do pooly shallow, but try it deeper.
I sold my Mark IIs to try other units. I have an Excal 1000, because I can hunt anywhere in Galveston or lakes. There are no limitations. The unit has an iron mask and it works killer. I have upgraded my PI to an Aquasearch. It is a limited edition, hand built PI. The units are made in England by Eric Foster, who is the PI master of technology. I was just getting used to it when I broke it, like I told you before. Can't wait to get her back. MrBill is loving on her for me. Good luck and don't hesitate to PM me if there is anything else I can help you with. GH