I use this on boat dives that are being made to salvage something, usually mooring anchors that are in the 200-250lb range. The come-a-long is operated by the surface crew not by the diver so it is not in the water. This makes it easier on the diver, saves air not having to filling a lift bag and allows you to lift the object out of the water and onto the boat. Like any other piece of equipment it is cleaned after every use and I have been using the same one for a couple of decades.
Another, cheaper alternative would be to use a pair of mountain climbing carabiners and 1/4" nylon line to form a block and tackle for small objects in shallow water. This should be set up as double tackle, more then that and the line will bind up on itself. As before you set this up so it is the surface crew doing the pulling not the diver.
PS: Just to be clear these are two versions of the same tool. They will only work if BOTH ends are attached to something. They are alternatives to a lift bag in cretin situations not a replacement for lift bags in every situation.
