GWorks headboards are 115mm, and they are a mixture of 3mm, 4mm & 10mm aluminum. All our filler components are located at the headboard. We also use this space to mount our water pumps which can be accessed via the removable inspection plates on the front of the headboard.
The headboards are also a great way to run cables neatly for 12v setups. Our trays work in tray top size - you can also add the headboard along the overall length. e.g. 1600mm tray top is 1715mm overall length on the vehicle.