On the south-western side you should be able to spot a piece of ventilation shaft and behind it you'll find a small opening in the wall.

This particular area has a number of Gas anomalies in it, so tread carefully. This stash is located inside a tunnel in the water-filled area on the northern side of the Cement Factory. The three stashes are all located in Jupiter: You can have Nitro unblock the module for you, which will net you the location of the stashes.

While you can locate and loot the stashes on your own, you can also get some assistance by retrieving the Memory module (blocked) from the crashed UAV in the north-western corner of Jupiter. First of all, they provide you with some extra medical supplies and ammunition, and eventually you'll find the unique Strelok's SGI-5k assault rifle - an excellent weapon in my opinion second, they contain a total of three notes written by some of the faction members these notes can either be sold to Owl, or if you hold on to them they can be given to Strelok in Pripyat which will earn you the Keeper of Secrets achievement. The stashes are important for several reasons. These are not traditional stashes as the items are located inside containers, and they always contain the same items in the same order no matter which stash you loot first also, they contain notes from the factions members that provide a little insight into who they are. In Jupiter you can find three special stashes that I refer to as the Streloks faction stashes.

This section provides information about the three special stashes, belonging to Strelok and his faction, that can be found in S.T.A.L.K.E.R.: Call of Pripyat. The Zone Survival Guide - Call of Pripyat - Streloks Faction Stashes

Call of pripyat factions