Doors and hatches
Black Trailer Door, No Window
Press & hold Activate to lock it or set a combination. Repair with a construction tool using the secondary action.
Harvest drops
Iron× 5-10
Taken apart with a harvesting tool (axe, pickaxe, shovel), before perks and tool bonuses.
Drops when destroyed
- Iron× 10
When it collapses
Falling, it leaves 
Scrap Metal Pile (75% of the time) where it lands.
Where to find (3 POIs)
NDC Checkpoint Three (tier 4), HSP Distribution Center (tier 3), Bunker Buildsite #5.
Points of interest built with this block (any of its variants), the highest tiers first, from the game's prefab files.