The 4 casters replace the legs on the appliance to make your machine portable Simply screw the casters into the holes below each corner of the machine Each caster has a locking lever which locks the appliance in place once it has been moved to the desired position This safety feature prevents the machine from moving or rolling around Features . The Casters replace the legs on the appliance to make your machine portable. Locking lever feature prevents the machine from moving or rolling around. Set of 4 Casters Specifications . Weight 5 5 lbs