EC Technology via Amazon offers its EC Tech 22,400mAh External Battery Pack in Black/Red, model no. B30-MET22400BR-1, for $49.99. Coupon code "2CTHM6P2" cuts it to $39.99. With free shipping, that's $111 off list and the lowest total price we could find, although we saw it for $8 less last week. The battery pack features an LED status bar and dual outputs to charge two devices at once.