De Klaver, or De Greate Klaver (the Great Clover), is a hollow post mill on the northwest edge of Bolsward, restored to working order. It was built to drain the surrounding low-lying polderland and is operated occasionally by volunteer millers. The structure is one of the more elegant of the regional drainage mills.
It is freely visible from the road and accessible on foot from the centre in around 20 minutes. Combined with the nearby Lonjé Molen it makes a short windmill walk around the town's edges.