A hyperdrive significantly faster than the Quantum I Hyperdrive. It achieves the second quantum rate of hyperspace travel, 1.25 Earth minutes/LY.[1]
The Quantum II unit was thought to be enormous, barely fitting within a GP Hull No. 4, this has been revealed as being untrue following events centered around the Fleet of Worlds.
The first ship to have one was the Long Shot. Others were the Kzinti ships Destroyer and Lance of Truth.[2] The Ringworld itself was fitted with Quantum II Hyperdrive functionality by the Tunesmith as Protector.[3]