Usually, the standards ordered will be forwarded directly to the address stated, through a forwarding agency which has been granted the required transport licences. Deliveries abroad will in certain cases be sent by air freight. The resulting transport costs will be invoiced in addition; for budgetary reasons, the PTB is not in a position to integrate the transport costs into the total costs as is common practice in private firms. For the delivery of radioactive standard sources only the General Terms and Conditions of Business (AGB) of the PTB are exclusively valid.