Overflux Capacitor

The Overflux Capacitor is an drop and it is a  item drop from the  Sven Packmaster and is used in the crafting recipe the Overflux Power Orb. The chances of it dropping are 5 in 13000 (1 in 2600 or ~0.0385%). The drop chance for the Overflux Capacitor is about 28.5% lower than the drop chance of the Grizzly Bait.

Trivia

 * Between the Scythe Blade (After 0.7.5 Update), Digested Mosquito, and the Overflux Capacitor, the latter seems to be worth more than the former two, going for higher prices on the auction house, This is because the Capacitor is required to make the Overflux Power Orb, which, when compared to its fellow elite tier slayer items, Mosquito Bow and Reaper Scythe, is more useful. The Orb applies several buffs to the player whereas the Mosquito Bow barely beats the power of the Runaan's Bow, as well as the Reaper Scythe being nerfed, making it the best of the items.
 * This item's name might be a reference to the Flux Capacitor in Back To The Future