Stalker: Call of Pripyat → Quests → Compass
Boroda (and the Sultan, too) needs this rare artifact. Noah, who lives on an old barge north of Skadovsk, has it. If you're on good terms with the stalkers, go to Noah and politely ask him for the artifact. Then, after you give it to Boroda or the Sultan... go to Noah again and politely ask for the artifact. This time for personal use.
The third time, you'll earn the honorable status of extortionist and a bullet to the head, so I don't recommend begging. Alternatively, you can kill Noah outright. Although, in my opinion, this isn't the best option, but if you're working for the Sultan...
Source: gamer.ru
See also:
Treasure Hunting in Terraria
Fallout Tactics: Explosives
Chemical Uses of Aldehydes