The drive socket connects the motor to the blade assembly, and serves as a safety mechanism to protect the motor from damage if the blade assembly becomes jammed or blocked during operation. Specifications: Item: Drive Socket 891 Material: Metal Color: Black Height: 1 Inch / 26 mm Outer Diameter: 1.57 Inch / 40 mm. Hole size: 1/4 Inch / 6mm square center hole Completed with Allen wrench COMPATIBLILTY: BarBoss, BarBoss MP, BarBoss Advance,Vita-Pro, Vita-Prep 3, Vita-Prep,Touch & Go On-Counter, Touch & Go In-Counter, T&G 2 On-Counter, T&G 2 In-Counter. Quiet One 220-240V On-Counter, Quiet One 200-240V In-Counter, Quiet One 120V On-Counter, Quiet One 120V In-Counter, Quiet One 100V On-Counter, Quiet One 100V In-Counter. Portion Blending System Adv, Portion Blending System. Drink Machine Variable Speed, Drink Machine MP, Drink Machine Advance, Drink Machine 45 Sec Timer, Drink Machine 20 Sec Timer, Drink Machine 2-Step Timer, Drink Machine 2-Speed.Blend Station MP On-Counter, Blend Station MP In-Counter, Blend Station Adv On-Counter, Blend Station Adv In-Counter. Package Includes: 2Pcs x Blender Drive Socket 891 2Pcs x Allen wrench