This is a replacement tray for those tilt-out trays that are in front of a sink.
You may want to remix the “Middle” to get the desired size for your needs. As designed, this provides for a 308mm (12-1/8 inch) hole-to-hole spacing.
No supports should be needed (the model includes the supports).
2023-07-03: Major rework to simplify the model. There are now only three parts to print. You now only need to remix (resize) the “Middle” to adjust to your specific needs.