of this paragraph must prepare the mailings as follows:

(i) Each piece must include the complete ZIP Code in the address.

(ii) Identical pieces (nonidentical pieces may voluntarily be merged with identical pieces).

(a) When there is sufficient quantity of identical pieces for a three-digit ZIP Code area to fill a sack approximately one-third full the mailer must place the pieces in a sack labeled for the area.

(b) If the identical pieces remaining after the three-digit sort for any State are sufficient to fill a sack approximately one-third full they must be placed in a sack labeled for the State.

(c) All identical pieces remaining after the State sacks have been prepared must be placed in sacks labeled "Mixed States."

(iii) Nonidentical pieces.

(a) All nonidentical pieces must be merged and presorted by State. When there is sufficient quantity for a State to fill a sack approximately one-third full, the pieces must be placed in a sack labeled for the State.

(b) All nonidentical pieces remaining after the State sacks have been prepared, must be placed in sacks labeled "Mixed States."

(iv) The total weight of pieces (identical or nonidentical) placed in one sack must not exceed 80 pounds.

(6) The address on each piece mailed at the rates provided by § 135.1 (c) and (d) must include the complete ZIP Code. When 5,000 or more identical pieces are mailed at these rates during a single day and there are enough pieces for the same destination to fill approximately onethird of a sack, they must be presorted and placed in sacks in accordance with the instructions contained in § 134.4 (c) of this chapter, as follows: Subparagraph (2); and subdivisions (i) (b), (ii) (b), (iii) (b), (iv) (b), and (v) (b) of subparagraph (6). When 1,000 or more but less than 5,000 identical pieces are mailed at these rates during a single day and there are enough pieces for the same destination to fill approximately onethird of a sack, they must be presorted and placed in sacks in accordance with the instructions contained in § 134.4 (c) of this chapter, as follows: Subparagraph (2); and subdivisions (ii) (b), (iii) (b), (iv) (b), and (v) (b) of subparagraph (6).

(b) Application of rates. (1) The rates in § 135.1 (a) and (b) are applied

36-087-70-8

on the basis of weight of the individual piece and the zone between the sectional center facilities of the post offices of mailing and delivery. Articles addressed to military post offices overseas (Army, Air Force, Fleet post offices, and Naval vessels) require postage at the zone rate applicable between mailing office and post office shown in the address.

(2) There is a local zone which is defined by the Postmaster General from time to time and eight numbered zones which are determined as follows:

(i) The United States and its territories and possessions are divided into units of area 30 minutes square, identical with a quarter of the area formed by the intersecting parallels of latitude and meridians of longitude. Each unit of area is designated by a number.

(ii) The zones are based on a straight line distance between the unit of area in which the dispatching sectional center of the mailing post office is located and the unit of area in which the receiving sectional center facility of the post office of address is located, measured from the center of one unit to the nearest point in the other.

(iii) An official zone chart prepared for each sectional center will be used to determine zones from all postal units within the sectional center area. The chart to be used is identified by the inclusive ZIP Codes assigned to postal units in the sectional center. Each chart lists the first three digits (prefix) of the ZIP Codes of all sectional center offices and to the right thereof the applicable zone.

(iv) To determine the zone distance from the office of mailing to the office of address, refer to the zone chart for use at the office of mailing and locate on the chart the first three digits (prefix) of the ZIP Code of the post office of address. To the right thereof appears the zone.

(v) An official Zone Chart may be obtained free by request to the postmaster at the office of mailing. For ZIP Code numbers, consult the national ZIP Code Directory. See § 114.2(b) of this chapter.

(3) The rates in § 135.1 (c) and (d) are computed on the basis of the weight of the piece regardless of the zone to which addressed.

(4) The local rate in § 135.1 (a) and (b) applies to parcels mailed at any post office for local delivery at that

§ 135.4 Payment of postage.

Mailers of fourth-class articles may

Redesignated

use any method of paying postage.
[26 F.R. 11551, Dec. 6, 1961.
at 31 F.R. 15350, Dec. 8, 1966]
$ 135.5 Additions.

(a) Required-(1) Return address. The return address of the sender must be shown on all fourth-class mail. See § 135.2(a) (5) concerning packages mailed at the library rate.

(2) Special markings. See §§ 121.6, 135.1(b) (1) (i), 135.2(a) (4) and (5), and 138.3 of this chapter for special markings required.

(3) Customs declarations. See §§ 125.7 (d) and 127.2 of this chapter concerning need for customs declaration forms for packages addressed to the Canal Zone and to certain military post offices over

seas.

(b) Permissible. (1) The following written additions may be placed on the wrapper, on a tag or label attached to the outside of the parcel (see § 123.2(b) of

this chapter for space requirements), or inside the parcel, either attached to an article or loose:

(i) Marks, numbers, name, or letters descriptive of contents.

(ii) Please Do Not Open Until Christmas, Merry Christmas, Mom & Dad, Happy Birthday, Mother, With Best Wishes, John Doe, and similar inscriptions.

(iii) Instructions and directions for the use of an article in the package.

EXAMPLE: Directions for use of prescription medicine.

(iv) Manuscript dedication or inscription not in the nature of personal correspondence.

(v) Marks to call attention to any word or passage in text.

(vi) Corrections of typographical errors in:

(a) Circulars or printed matter. Handwritten or typewritten changes or additions in the body of a circular are limited to corrections of actual typographical errors.

(b) Proof sheets. Corrections in proof sheets include corrections of typographical and other errors, alterations of text, insertion of new text, marginal instructions to the printer, and rewrites of part if necessary for correction. Corrections should be on margins or attached to the manuscript. Do not enclose manuscript of another article.

(vii) Handstamped imprints, except when the added matter is in itself personal or converts the original matter to a personal communication.

(viii) Any printed matter mailable as third class.

(2) An invoice whether or not also serving as a bill relating solely to the matter with which it is enclosed, may be enclosed or placed in an envelope (marked Invoice Enclosed) attached to the outside, showing any or all of the following:

(i) Names and addresses of sender and addressee.

(ii) Names and quantities of articles enclosed.

(iii) Description of articles enclosed, including price, tax, style, stock number, size, and quality; and if defective, nature of defect.

(iv) Order or file number, date of order, date and manner of shipment, shipping weight, and postage paid.

(v) Initials or name of packer or checker.

[27 F.R. 11766, Nov. 29, 1962, as amended at 29 F.R. 8008, June 24, 1964; 33 F.R. 12283, Aug. 31, 1968; 33 F.R. 18156, Dec. 6, 1968. Redesignated at 31 F.R. 15350, Dec. 8, 1966] § 135.6

Enclosures.

(a) Catalogs. Catalogs mailed at the rates in § 135.1(b) (1) and (2) (i) may have any or all of the following enclosures, provided the loose enclosures form only an incidental portion of contents:

(1) Order forms, reply envelopes, and circulars.

(2) One each of a printed blotter, illustrated display sheet, poster, dealer's card, or similar printed advertising matter.

(3) An invoice. (See 135.5 (b) (2).) (b) Special fourth-class and library rate (1) Books. The following may be enclosed with books:

(i) Incidental announcements of books, appearing in book pages or as loose enclosures. This includes an addressed envelope or post card, a single order form, and a printed circular, each of which must relate exclusively to books.

(ii) An invoice (see 135.5(b) (2) of this chapter).

(2) Sound recordings. The following may be enclosed with sound recordings mailed at the rates in § 135.1(c):

of

(i) Incidental announcements sound recordings appearing on title labels, on protective sleeves, on the carton or wrapper, or in form of loose enclosures.

(ii) An invoice. (See 135.5(b) (2).)

(3) All other items listed in § 135.2(a) (4) and (5). Enclosures are not permitted except as provided in § 135.5(b) (2).

[29 F.R. 8008, June 24, 1964, as amended at 30 F.R. 7396, June 4, 1965. Redesignated at 31 F.R. 15350, Dec. 8, 1966]

§ 135.7 Sealing.

Fourth-class mail must be wrapped or packaged so that it can be easily examined. Mailing of sealed parcels at the fourth-class rate of postage is deemed to be the consent of the sender to postal inspection of the contents. Patrons who desire to assure that their parcels will not be opened for postal inspection, should, in addition to paying the first-class rate of postage, plainly mark their parcels "First Class" or with similar endorsements.

[26 F.R. 11552, Dec. 6, 1961. Redesignated at 31 F.R. 15350, Dec. 8, 1966]

(a) Fourth-class articles may be mailed at a post office, branch, or station, or handed to a rural or star route carrier. They may not be mailed at railway post office cars.

(b) Parcels exceeding the limits of size and weight for articles mailed at first-class post offices that originate in and are prepared in cities or towns served by first-class post offices may not be diverted to other post offices or to a rural or star route carrier for mailing.

[26 F.R. 11552, Dec. 6, 1961. Redesignated at 31 F.R. 15350, Dec. 8, 1966]