This pin is mandatory if you want to keep the paint of the cargo doors from your split window bus nice, and prevent these doors from dents or damage.
Together with the door check strap BBT ref 0438-600 (-60) or 0438-610 (61-67) and the door check strap bracket BBT ref 0438-620 this pin prevents the cargo doors for opening over 90°. But when properly installed this pin can be taken out by hand for opening the door further for wide loads or where space not allows . a super nice combo we have all complete now, make sure to get yours!