All domestic coolers with "ship" included in the product name will include a FedEx Priority Overnight label to send the milk back to your baby. However, to ensure timely delivery, FedEx imposes cutoff times for tendering (dropping off) overnight shipments.
If a package is tendered after the cutoff time, it will not be eligible for overnight delivery, and the delivery may be delayed by one business day.
FedEx-approved shipping locations and their last pick-up times can be found here. Whenever possible, it is highly recommended to use an actual FedEx Office/Ship Center rather than an onsite location.