BoardingBlue Personal Item Under Seat Duffel Bag for the Airlines of American, Frontier, Spirit Airlines Personal Item Under Seat for most airlines in the US Size Zipped-In: 16"x8"x12" for most airlines (cu.in 1536) Size-out: 16"x14"x12" expandable bag multi-use Friendly Reminder: Please Do NOT Pack Too Much. Or It may cause the bag oversized