Western Shaft Key
Western Shaft Key is a key found in the level Inside Menkaure's Pyramid in The Last Revelation. It's used in the level Inside the Great Pyramid along with three other shaft keys.
It's important not to leave the level Inside Menkaure's Pyramid before the Western Shaft Key is found, since after proceeding into the level The Mastabas, it's not possible to re-visit the level. Having all four shaft keys opens the exit in Inside the Great Pyramid. Not having the key won't be a problem if one uses the level skip cheat, but doing so may cause some problems (see The Last Revelation Cheats for further details).