(d) Certificate. Any paper, records, tapes, or other materials intended for the production of reading matter for the blind which is mailed free of postage under § 138.4(b) shall in addition to the markings required in paragraph (b)(1) of this section have the following certification on the address side of the container and on any invoice or packing slip enclosed therein:

This certified that the contents of this parcel are the property of (name of the owner) to be used for production of reading matter for the blind, and are mailed free of postage under the provisions of 39 United States Code 4654.

§ 138.6

Weight and size limits.

(a) Publications and other reading matter mailed under § 138.3 (a) and (b): Weight, 15 pounds; size, same as provided in § 135.3 (b) of this chapter.

(b) Reproducers and other appliances mailed under § 138.4(a): Weight, 70 pounds; size, 100 inches length and girth combined.

(c) Paper, records, tapes and other materials mailed under § 138.4(b): Weight and size-same as provided in § 135.3 (a) and (b) of this chapter.

tied or otherwise attached to the address side of a second-, third-, or fourthclass mailing piece including airmail articles. The envelope must be placed on the address side of the principal mailing piece. Combination envelopes or containers having separate parts for the two classes of mail may be used. See § 134.8 concerning the sealing of thirdclass mail.

(b) Addressing. The name and address of the sender and the name and address of the addressee should be placed on both the principal mailing piece and the attachment. If both names and addresses do not appear on both pieces, the sender's name and address must be placed on one and the name and address of the addressee must be placed on the other. Combination containers having inseparable portions or compartments are mailable with the names and addresses on only one portion.

(c) Postage. Postage on the second-, third-, or fourth-class mail must be prepaid at the appropriate rate and must be placed in the upper right corner of the address space. Postage at the appropriate first- or single-piece third-class rate must be paid for the attachment and affixed to it. If mailed by air, postage at the airmail rate must be paid for the letter.

(d) Markings required. First-class attachments may be marked "FirstClass" or "Letter Enclosed". Third-class attachments must be marked "ThirdClass".

§ 139.3 Mailing enclosures of different classes.

(a) Enclosures mailed with secondclass and controlled circulation publications (1) First- and third-class enclosures. Separate and independent letters or other first- or third-class mail may be mailed as enclosures with second-class and controlled circulation publications.

(2) Payment of postage. Postage at the appropriate first- or single piece third-class rate must be paid for each separate enclosure. Pieces of related matter enclosed with a publication as a unit may be regarded as a single enclosure for purpose of computing postage. The postage may be placed on the enclosure by using precanceled or meter stamps, or the postage may be placed on the outside envelope, wrapper, or cover. Postage at the second-class pound or per copy rates or postage at the controlled circulation rates must be paid on the

publication in the manner prescribed by part 126 of this chapter. When postage at the transient second-class rate is paid on the publication, follow the procedure in paragraph (b) of this section.

(3) Marking required. When postage for the enclosure is placed on the outside envelope, wrapper, or cover of a publication, the mailer must mark each piece as required by § 139.3 (b) (5).

(b) Enclosures mailed with third- and fourth-class parcels-(1) First-class enclosures. Letters may be enclosed with books, catalogs, and merchandise mailed at third-class rates. (See 139.2 for mailing letters with other third-class matter.) Letters may be enclosed in fourth-class parcels. Postage at the first-class rate must be paid for each letter.

(2) Third-class enclosures. Thirdclass mail may be enclosed in a fourthclass parcel mailed at the special rates in § 135.1 (b), (c), and (d) of this chapter, and § 138.1 of this chapter. Postage at the single-piece third-class rate must be paid for each enclosure except the items listed in § 135.6 of this chapter.

(3) Placement of enclosure. The enclosure should be placed on top of other items in the parcel when practical.

(4) Payment of postage. Postage for the enclosure must be placed on the outside of the parcel. It may be added to the postage for the parcel and the total amount paid together, or the postage for the enclosure may be affixed separately from the postage for the parcel.

(5) Marking required. The mailer must place the endorsement "First-Class Mail Enclosed" or "Third-Class Mail Enclosed" on each parcel below the postage and above the address. The endorsement may be handstamped, handwritten, typewritten, printed, or put on by any other method.

(c) Penalty-(1) Failure to pay. If postage is not paid at the appropriate rate in the manner provided for by paragraphs (a) and (b) of this section for letters or other pieces of first- or thirdclass mail, the second-class publications or the third- or fourth-class parcels in which they are enclosed will be subject to the higher rate applicable to the enclosure.

(2) Concealment. Mailers are subject to a fine of not more than $100 if they knowingly conceal letters or other pieces of first- or third-class mail in secondclass publications or in third- or fourthclass parcels without paying the appro

priate rate of postage on the enclosures in the manner provided for by paragraphs (a) and (b) of this section. § 139.4 Treatment.

(a) Forwarding. Pieces of second-, third-, or fourth-class mail having other classes of mail enclosed under the combination mail arrangements provided for by § 139.2 are subject to the same conditions for forwarding as single pieces of second-, third-, or fourth-class mail (see Part 157 of this chapter). If the enclosure is first-class mail, that fact will not affect the conditions of forwarding.

(b) Return. (1) Undeliverable combination mail pieces, including those which cannot be forwarded, one part of which is first-class mail, shall in all cases be returned to the sender subject to the charge for return according to its class. See § 158.2 (b) through (f) of this chapter. The weight of the first-class piece will not be included when computing the charge for return of the second-, third-, or fourth-class portion.

(2) Any undeliverable combination mailing piece which does not include first-class matter shall be disposed of as provided in Part 158 of this chapter.

(3) If for any reason an undeliverable combination mailing piece, one part of which is first-class mail, is not returnable to the sender, it will be treated as provided in § 158.7(b) (1) of this chapter. (39 U.S.C. 4105) [30 F.R. 11604, Sept. 10, 1965; 30 F.R. 15213, Dec. 9, 1965]

§ 139.5 Special services.

Combination mailing pieces may be sent as special delivery or in the case of fourth-class parcels as special handling, and only one fee applicable to the parcel is required. Combination pieces may not be registered. They may be sent insured or COD, the insurance to cover only the value of the parcel.

PART 141-STAMPS, ENVELOPES, AND POSTAL CARDS

inches long and are located 1⁄2 inch from the bottom of the envelope. In size 634, the window is located 8 inch from the left edge, in size 9 and 10 it is 3/4 inch from the left edge.

(5) Dimensions of envelopes. Size 64

3% by 61⁄2 inches. Size 9 (manufacture was

discontinued 12-31-64). 3% by 8% inches. Size 10----. 4% by 91⁄2 inches.

(6) Private printing. Stamped envelopes may be privately printed in any style, provided at least 31⁄2 inches of clear space is left at the right end of the address side of the envelope.

(b) Postal cards available-(1) Cut single cards.

1 Current stocks being revalued by the affixing of 1-cent adhesive postage stamps.

All domestic postal cards (regular, commemorative, and airmail) are precanceled. Postal cards in sheets for use in printing must be cut to regulation size, 34 x 51⁄2 inches; however, domestic regular and domestic airmail cards may be cut to 3 x 5 inches. Cases may be broken for sale to printers. Return addresses are not printed on postal cards by Post Office Department.

(c) Aerogrammes. 11 cents each. (See § 241.5 of this chapter.)

[28 F.R. 11886, Nov. 7, 1963, as amended at 30 F.R. 11678, Sept. 11, 1965; 30 F.R. 13215, Oct. 16, 1965; 31 F.R. 5198, Mar. 31, 1966. Redesignated at 31 F.R. 15350, Dec. 8, 1966]

(b) How to order printed stamped envelopes. Prepare form 3203, Order for Printed Stamped Envelopes, as illustrated below. Submit the order through the post office named in the return address. However, if undeliverable letters are to be returned to the main office of a firm in another city, envelopes may be

ordered at the post office where they will be mailed.

(c) Return address requirements. (1) The printed return address must include:

(i) Local address (only one of the following-whichever one is necessary to ensure safe return of undeliverable letters; rural route number and box num

• Minimum order