To use a PO, once you have completed all of the details on your order, click "Pay by P.O". You may then email your PO to us at email@example.com or fax it to us at 1-888-782-3521. We will then invoice you. We cannot fill your order until we receive your PO. Our terms are net 30 and there will be a 20% penalty for any invoice not paid within 30 days.