Key Specifications: 1.The Kneading Massage cushion comes a screw located on the back of the unit to protect 2.The massage mechanism during shipment. Which must be removed before the first use to allow the kneading feature to function. 3.Use the provided allen wrench. 4.Then properly dispose of the screw. 5.Warning-Failure to remove screw may cause permanent damage to the massage cushion.