It looks just like the normal cable come-a-longs that you can buy at Home Depot, Lowes, Walmart, etc. This one is nicer since it has a rope that is safer than a steel cable.
In my younger, less intelligent days I kept one in my cherokee for recovery. Only time I ever truely used it was pretty useless, very hard to use and barely made a difference compared with the amount of effort I put in. Later I used it a couple times as a tow rope extension, which broke it.
They do have their uses - great for pulling fence, tensioning guy wires, I have even seen them used to pull an engine when attached to an overhanging tree limb. All in all they are useful around the house but it burned a lot of room for little value as a recovery device.