Does not open any Special Rooms, including those that require pickups to unlock. Doors won't be opened even if they were open already (such as Treasure Rooms and Shops on the first floor, Sacrifice Rooms, etc.) or have been entered before.
Does not open doors to Red Rooms if those door are created while there are enemies inside the current room.
4.5 Volt / Jumper Cables: Provides infinite charges by clearing some enemies then leaving the room, and repeating.