Fuzzy2u, Wood or wire(better)-a small (12x12x18) rectangular box with 2 holes in the top about 5 inches in diameter with about 3 or 4 inches of pvc in each hole like recessed chimneys. Make one of the sides on hinges with a latch of some sort for dumping out the crabs, snails etc. Crabs crawl up on top and fall thru holes and can't get out. We catch 100's right under our boat. Hoop-how do you do it?