hi .making a pass through isnt that difficult .we use two z section ally channels ,one sits inside the other but upside down .one fixed to the truck the other to the box . with a rubber foam insulation /rattle stopper. have the corners welded and water runs off the sides .
i call ed them z sectioned but theyt arent proper z but up across then up again .
dust does work its way in but then dust as that magic trick anyway.
i call ed them z sectioned but theyt arent proper z but up across then up again .
dust does work its way in but then dust as that magic trick anyway.