This sand mould has the shape of a ring cake: ribbed all the way round, with a little chimney through the middle. It is made of glossy plastic and the colour may vary: which one you receive is not settled in advance.
Fill, press, turn over, lift. That is the whole game, and it keeps its hold because the sand behaves differently every time: too dry and the cake collapses, too wet and it sticks in the mould. Do it a few times and you work out for yourself how much water belongs in the bucket.
It works as well in the sandpit as on the beach, and it rinses clean under the tap. Small enough to slide into the back of the beach bag, next to the bucket and the spade.