Code of Federal Regulations Title 39. Postal Service § 39.762.11 General

(a) Disbursement Postal Money Orders have words of negotiability—“Pay to the order of”—printed on their face, while other postal money orders simply bear the words “Pay to” on their face;

(b) Disbursement Postal Money Orders, unlike other postal money orders, bear on their face the phrase, “This special money order is drawn by the Postal Service to pay one of its own obligations.”;  and

(c) The amounts of Disbursement Postal Money Orders are printed in words as well as numbers, while the amounts of postal money orders available at post offices are printed in numbers only.