This is the largest of the round Pool Covers by Didak Pool: the box reads FIT ROUND POOL 3.96m and prints 396 cm next to it. A cover for a substantial round above-ground pool, the size you can genuinely swim lengths in.
After a swim you pull it across the pool and let it hang over the top rail. The water surface then stays largely clear of leaves, grass and dust, even when the pool goes unused for a few days.
Note what is in the box: the cover, and nothing else. The pool, the frame and the legs in the picture are only there to show which type of pool the cover fits. Measure your own pool first - 3.96 m across is the size this one is made for.
A replacement part, or a second cover, for anyone with a round pool that size standing in the garden.