The effective locking system guarantees perfect stability of the bowls and a consequent elimination of metallic noise. The package contains: * A base * A vertical bar * Two knobs * A support for the bowls * A stop device / bowls * Two stainless steel bowls Assembly instructions: * Assemble the support bar into the base and secure it by tightening the screw. * Insert the bowl holder into the bar and lock it at the desired height with the appropriate knob. * Finally, lock the bowls with the device equipped with a knob