Blue Lunch Box

Maybe one of the geocaching targets.

161205 could mean 16/12/2005 was when it was placed there?

Other than that , no idea.

Banjo (WA)

goodday khb
i think banjo may be right member geocacher would have the answer but if you go to the geocache site you maybe able to get some more details
did you put your name and date on/in it and leave it there?
if you look at the geo cache site you may be able to claim it as a first if it si registered
steve

What state is Rudall? you can do a postcode search in Geocaching.com and it will tell you all the caches in that area.

Definately sounds like a cache. Most are lunchbox size and hidden under rocks or fallen trees and stumps.
Usually they will have some items inside for swapping as well as a book or a small writing pad to be used as a log. Most caches, if they are big enough will also have an information page about Geocacheing and what to do with it when you inadvertantly find one.
Seeing as this one only had 2 rocks in it and a number written on it, it may be a clue (or part of a co ordinate) for a multi part cache. Or someone else has also found it and taken everything that was in it.