These wooden raisers are available in either screw or bayonet fitting and are designed to replace existing castors. The black hardwood raisers increase the height of beds by 75mm (3") or 100mm (4") and are designed for all beds with castor legs. In order to fit these items the existing castor is replaced and the required screw or bayonet raiser used, depending on the castor fitting. Product weight: 75mm (3"): 0.6kg (1.3lb). 100mm (4"): 0.9kg (1.9lb).