A pack of capacitors - one of the basic electrical components around. They're not that rare in the Zone, as they're used for hi-tech equipment upgrades, but this sort of capacity is not normally required.
― In-game description
A pack of capacitors is an item in S.T.A.L.K.E.R.: Call of Pripyat.
Description[]
It is one of the materials that Nitro requests the player to find as part of his side mission Radio equipment. As with the rest of the materials, this item is found inside the Yanov Cement Factory. It is found in the second floor of the building, on a table by a window in a large room with rusty walls.