The cache is normal film canister that is attached with a magnet. Getting hold of it requires you to get over the safety fence and grab it. Note that there is no pencil in the box, so you have to bring your own.
Falling from the location will cause almost a certain death, so this is only recommended for experienced and skillful cachers. Taking a safety rope is highly encouraged, although one is not needed to find the cache.
If you think you need help in finding a way to climb to the cache, see the attached spoiler photo.