Orders are processed upon receipt. Actual shipping time is contingent upon the availability of merchandise and credit verification. Most orders are shipped within 1 or 2 business days of receiving your order. In the event of delays, every effort will be made to contact you by phone, e-mail, or mail. If the delay is due to backorder, you will receive a notice and be given the choice to remain on backorder, substitute another item, or cancel your order.All oxygen cylinders are shipped empty unless otherwise specified.