Grey Iron Door
Press & hold Activate to lock it or set a combination. Upgrade & repair with a construction tool using the secondary action.
Upgrade path
Hit a placed block with a stone axe, claw hammer or nail gun while carrying the material of the next step: 6 hits per upgrade.
Crafting
Craft at Backpack · makes 1
Crafted as Iron Door: pick this one of its variants when you place it.
Forged Iron× 10
Harvest drops
Iron× 4-10
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 (58 POIs)
Area 7 (tier 5), Correa Rockworx (tier 5), Dishong Tower (tier 5), Grover High (tier 5), Haven Hotel (tier 5), Hybrid Mining (tier 5), Navezgane Athletics Complex (tier 5), Navezgane County Jail (tier 5), Navezgane General Hospital (tier 5), The Last Sunset Nursing Home (tier 5), U.S. Army Post #7 (tier 5), Beanthere Coffee Company (tier 4), Don Vittorio Spagetto Residence (tier 4), Doominium Tower (tier 4), Fort Quonset (tier 4), Green Hill (tier 4), Hybrid Energy (tier 4), Infested Warehouse (tier 4), Installation Blue Ridge (tier 4), Joe's Junction (tier 4), NFD Downtown HQ (tier 4), Olgiddy & Brother Advertising (tier 4), Pineballs Bowling (tier 4), St. Moe's Cathedral (tier 4), Super Shamway (tier 4), Carl's Cars (tier 3), Mamma Pizza (tier 3), Navezgane Falls Diner (tier 3), Scarecrow Fields (tier 3), The Boobie Trap (tier 3), Vick Garrison's Pedipawn (tier 3), Bart's Salvage (tier 2), Blue Trailer Trucking (tier 2), Congregation of Blind Faith (tier 2), Downtown Post Office (tier 2), Hersh Farm (tier 2), Luigi's Pizza (tier 2), Maggie's Corner Cafe (tier 2), The Bennett Residence (tier 2), Bobcats Bar (tier 1) and 18 more.
Points of interest built with this block (any of its variants), the highest tiers first, from the game's prefab files.