Doors and hatches
Grey Steel Garage Door 3x3
Press & hold Activate to lock it or set a combination. Upgrade & repair with a construction tool using the secondary action.
Harvest drops
Iron× 750
Taken apart with a harvesting tool (axe, pickaxe, shovel), before perks and tool bonuses.
Drops when destroyed
Spring× 8-12
Mechanical Parts× 8-12
When it collapses
Falling, it leaves 
Wood Debris (Terrain) (75% of the time) where it lands.
Where to find (3 POIs)
Pass-N-Gas Store #08 (tier 1), The Powell Residence (tier 1), Dell Farms.
Points of interest built with this block (any of its variants), the highest tiers first, from the game's prefab files.