Wikia

The Quantum Helmet is extremely powerful, but also extremely expensive, having two Iridium Plates as components. A charged helmet will allow its user to breathe underwater, replenish the user's hunger bar (it will go to one short of full then stop), and cure poison effects until the charge is depleted. Along with Gem Armor, this armor is the most powerful in Tekkit.

Like all other pieces of Quantum Armor, it is capable of storing up to 1 million EU, and can only be recharged in an MFS Unit, HV Solar Array or a Charging Bench MK3. This piece of the QuantumSuit is likely to consume the most EU, because of the "feeding" ability, which consumes additional EU while it is working. Please keep this in mind, as a helmet will fully decharge much faster than other quantum components and will make you vulnerable to damage.