You can never have enough storage in your Sprinter. We needed a place to store charging cables, USB chargers, sunglasses, and other small items. We had these made locally by Beckel canvas. Black canvas outer, orange vinyl inner that can come out to wash if needed. There's a grommet on the north end if you want to tie it down. We've never been able to loose it, even on the roughest terrain.
Always in reach, just the right size. Terrawagen canvas stuff box.