Dont make it easy! These are the infamous Bison Caches that you hear about. Each comes with a rubber O-ring to seal it against the elements and it also has two silver split rings of different sizes so you can attach it to a keyring (or actually use it as a geocache). They are made out of Anodised Aluminium and so are hard wearing and will last a long time.

Note: This cache does not come with a log roll and is sold seprately