its a box inside of a box the inner box is raised and lowered with cables ,some use chains with catches,the inner box usualy doesnt come completely out of the outer box,some use cable winchs like the the round about one for brining your boat up on the trailer. ,you simply raise and lower it to follow the tide up and down ,mind you ,you must place the tub in an area where the tide favors the use of this type ,usualy along a bar next to a big eel grass feeding grounds. they use them here for geese mostly, i will try and get a fella i know who hunts them to take some pics for ya ,no promises tho they are always shootin so pics are not taken most times...but i will try...