MODEL NUMBER - Vitamix Drive Socket Kit - 891. DURABLE & STRONG - The kit is made of premium material and strict tests had been performed for long lasting use. You don't need to worry about replacing it frequently, saving your time and the maintenance cost. COMPATIBLITY - The drive socket couples the motor to the blade assembly and protects the motor if the blade assembly is blocked from rotating. This replacement drive socket kit is not for use with the Vitamix XL. EASY TO INSTALL - It will take you about 10 minutes to replace the drive socket kit. DIY installation, full of accomplishment. size: Approximately 4.1cm in diameter Material: plastic colour: black Package Contents: 4 x Drive Socket 4 x Hex wrench Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.