Swivel Car Seat Base Heavy Duty Stainless Steel 360 Degree Rotating Swivel Chair Base Replacement for RV Commercial Vehicle Item Type: Swivel Car Seat Base Material: Stainless steel + carbon steel + hot rolled steel Rotation Angle: 0-360 degrees, forward or reverse Base Dimensions: Approx. 390x360mm / 15.35x14.17in Seat Mounting Hole Distances: 230mm, 260mm, 297mm, 304mm (or re drilled) Application: Unique swivel base for seat modification, convert fixed seats to swivel seats Installation: For seats too large, additional transition plate is needed for installation, for seats too small, re drilling is required. Installation of this base is dependent on your seat size. Fitment: for most RV, commercial vehicle, and engineering vehicle seats modification Installation Instructions: 1. Identify the seat base installation location and clean the appearance 2. Mark the drilling locations, drill holes using the drilling tool 3. Secure the seat base in installation position and fasten with screws 4. Mount the seat securely on the base for complete installation (Installation is somewhat challenging, it's highly recommended to seek professional engineers for assistance to ensure an excellent shopping experience, safety precautions should be taken during installation)