The Locker Key #106 is a key that Henry Townshend finds in Silent Hill 4: The Room. It is located in the home of Henry's neighbor, Room 301, of South Ashfield Heights. The key is behind a red poster on the wall beside another key, the superintendent's key. The key opens locker #106 of the small lockers in the main lobby of the apartments. Opening the locker isn't required, as it simply reveals the contents of Room 106's mailbox.
Henry's neighbor living in Room 301, a man named Mike, is obsessed over the tenant of Room 106, a nurse named Rachael. His obsession drove him to write to her fanatically and send her copious love letters. Upon opening locker 106 with the key Mike stole, Henry finds the mass of letters Mike intended Rachael to read, all of which have been untouched.