A wire cluster found on a defeated Big Daddy.

Do you guys have any idea there's a war on? If you don't follow proper maintenance on those Big Daddies, they burn through those R-34s like them Eve's Apple betties go through penicillin.
Pablo Navarro[src]

R-34 Wire Clusters are a plot item in BioShock. They are one of the components needed to assemble the Electromagnetic Pulse Bomb in the crawlspace behind Kyburz' office. They can only be found on the bodies of Big Daddies, be they pre-existing corpses found in Hephaestus (of which there are two: one in a room near the circuit breaker and one near the Electromagnetic Pulse Bomb), or from the corpses of Big Daddies killed while playing through the level. Big Daddies from other levels also drop R-34s, which can be useful for collecting R-34s as Big Daddies on earlier levels are easier to kill.

If the pre-existing corpses are searched before Jack begins collecting materials for the bomb, then they may not be searched again for R-34 clusters.