Seat Swivel Base 360 Degree Rotating Strong Load Capacity Heavy Duty Driver Side Chair Seat Base for Transit 150 250 350 Item Type: Heavy Duty Seat Swivel Base Material: Carbon steel + hot rolled steel Base Size: Approx. 460x460mm / 18.11x18.11in Rotation Angle: 0-360 degrees Rotation Direction: Forward or Reverse Application: Used for seat base modification, can transform the fixed seat into a swivel seat for easy adjustment of seat orientation, convenient for boarding or interacting with other passengers (only suitable for driver side) Installation Guide: If your seat is too large, additional transition plates may be required for installation, if your seat is too small, re drilling is needed, the installation of the seat base depends on the size of your seat Fitment: The following models can be installed directly without drilling 4 red holes for Sprinter 2007-2018 4 yellow holes for Sprinter and for Metris 2019-2020 6 purple holes for Sprinter 2002-2006 4 green holes for Transit 150 250 350 2014-2023 6 blue holes for Promaster 2014-2020 And also apply for T5 T6 (Re drilling required for installation on other models)