Complex of two locks at the mouth of the Willemsvaart in the IJssel. Small lock, built from 1818 to 1819. About an single drawbridge (1873). Large lock, passage width approx 12m., which a double drawbridge (1873). Both locks are beautiful inside lock doors in the abutments of the bridge, made of iron constructed. The locks are located in a ramp that is part of the built in 1598 Zwolle defense. Unique combination of a fortification and a water construction. The construction of the Zwolle-IJssel Canal in 1964 Willemsvaart lost its original function. The canal was largely muted to allow for traffic along the Veerallee.