As one of its daily deals, All4Cellular offers the refurbished Mophie Juice Pack Air for iPhone 4 and 4S in White (pictured) or Black/Silver, model no. 1145_JPAXP4, for $14.99 plus $2 for shipping. That's tied with our mention from a month ago and $10 under the lowest total price we could find for a refurb in any color today. (For further comparison, it's $28 under the lowest total price we could find for a new unit in any color.) This 1,500mAh battery pack provides up to an extra 6 hours of talk time in 3G or up to 12 hours in 2G. Deal ends today.

A 90-day All4Cellular warranty applies.