As one of its daily deals, Caloby offers the uNu Enerpak Vault 11,000mAh Battery Pack, model no. PB-01-11000BS, for $39.99 with free shipping. That's $5 under our mention from last month and the lowest total price we could find now by $5. It's compatible with most smartphones and tablets and features a 11,000mAh lithium polymer battery, ability to charge two devices simultaneously, and USB cable. Deal ends today.