Iron Door

Iron Doors are a type of door which can only be opened through a Redstone mechanism.

crafting
An Iron Door is crafted from 6 Iron Ingots.

6 Iron Ingots => 1 Iron Door

Trivia

 * The bottom half of the Iron Door in PE appeared glitched, like a broken glass pane.
 * This was fixed in a 0.10.x update.
 * They were non-stackable, similiar to wooden doors. They became stackable after Update 0.12.1.
 * Iron Doors were able to be obtain but using inventory editors before Update 0.13.0.