Car Shift Knob Boot Retainer, M12 x 1.25 Aluminum Manual Gear Shifter Stick Connector, Durable Gear Shift Lever Adapter/Retainer Holder for Manual Transmission Vehicles (Red) Color: Red Efficient Function: The car shift knob boot retainer fills the space between the bottom of the shift knob and the shift starter, securing a proper fit between the upper and lower sections.