There are generally four different types of cover. The two types of automatic cover can be taken off and put back onto the pool at the touch of a button. Both designs of auto cover also have the benefit of added safety: although they can not be sold on outdoor pools as 100% safe, they do dramatically lower the risk to children and animals, should they fall onto the pool with the cover on.
The slatted floating cover generally referred to as a 'rolldeck cover' can be recessed into a cover housing at the end of the pool, and at the push of a button floats over the pool surface. This type of cover can also be housed at the end of the pool, above water level, in a custom made housing; when activated, it floats over the pool surface.