Every letter carrier shall give bonds, with sureties, to be approved by the Postmaster General, for the safe custody and delivery of all mail matter, and the faithful account and payment of all money received by him. Each letter carrier and substitute letter carrier shall, at the time of his appointment, give bond in the sum of one thousand dollars. It is preferred that bonds furnished by one of the surety companies authorized to act as sureties on official bonds be given. The original bonds of two or more carriers or substitutes, appointed at the same time, may be given on a blanket or schedule form. Letter carriers transferred from one post office to another, and substitutes promoted to be regular carriers, must file new bonds, their former bonds terminating on the date of such transfer or promotion. A list of the companies authorized to act as sole surety on official bonds will be furnished upon application to the First Assistant Postmaster General (Division of Free Delivery). All bonds of carriers must be filed with the First Assistant Postmaster General (Division of Free Delivery). Every carrier, before beginning active service, shall take the official oath prescribed in Section 207, which oath will be retained on the files of the local post office, subject to the call of the First Assistant Postmaster General or to inspection by a post office inspector or other officer of the Post Office Department. Uniforms of Carriers. The Postmaster General may prescribe a uniform dress to be worn by letter carriers, and any person not connected with the letter carrier branch of the Postal Service who shall wear the uniform which may be prescribed shall for every such offense be punishable by a fine of not more than one hundred dollars, or by imprisonment for not more than six months, or both. Letter carriers and substitutes must procure uniforms at their own expense. Postmasters will advise and assist them in obtaining well-fitting suits of the prescribed material and at the best terms. Uniforms made according to the following specifications must be worn by all letter carriers: For Winter Uniform.