Over the years I've read lots of posts about lost M-Bags.

Anyway . . . just an
FYI for those who don't typically ship and receive M-Bags, that things changed with the last postal rate hike.
I saw a recent post about an M-Bag arriving quickly to Great Britain . . . from what I understand, there are no more surface M-Bags, just as there is no surface mail . . .
All M-Bags are Airmail now.
Here are the current rates to overseas:
Table 6: M-bags
Weight Not
Over 11.0 (lb.)
Rate Groups
1: $18.70
2: $24.20
3: $31.35
4: $49.50
5: $43.45
Each additional pound or fraction of a pound 1.70 (1), 2.20 (2) 2.85 (3) 4.50 (4) 3.95 (5)
1 Rate Groups: 1 is for Canada; 2 is for Mexico; 4 is for Australia, Japan, and New Zealand; for 3 and 5, see the "First-Class & M-bag Rate Group" column in the Country Listing.
2 Maximum weight limit: 66 pounds (including the tare weight of the sack) to all destination countries, except 44 pounds to Great Britain and Northern Ireland. M-bags that weigh less than 11 pounds are subject to the minimum 11-pound rate.
Note that Great Britain is the category 3 country listing.
Oh . . . and here are the complete rules - note that things like miniatures do not qualify. (easy enough to find on the
USPS website, but I'll cut and paste it anyway.
M-bags (Direct Sacks of Printed Matter to a Single Addressee)
Direct sacks of printed matter to a single foreign addressee, which are also known as "M-bags," are subject to the following conditions of mailing:
a. Minimum weight: There is no longer a minimum-weight threshold for M-bag usage. However, customers who tender M-bags that weigh less than 11 pounds are still required to pay the applicable 11-pound postage rate.
b. Maximum weight: 66 pounds (including the tare weight of the sack). Exception: Maximum weight to Great Britain and Northern Ireland is 44 pounds.
c. Service availability: M-bags can be mailed to all destination countries.
d. Allowable contents:
(1) All categories of printed matter can be enclosed in an M-bag. Printed matter is defined as paper on which words, letters, characters, figures, images, or any combination thereof, not having the character of a bill or statement of account, or of actual or personal correspondence, have been reproduced by any process other than handwriting or typewriting. Articles that meet the printed matter definition include newspapers, magazines, journals, books, sheet music, catalogues, directories, commercial advertising, and promotional matter.
(2) Certain categories of merchandise can be combined with printed matter in an M-bag provided that all of the following criteria are met:
(a) The merchandise items being sent are limited to disks, tapes, and cassettes; commercial samples shipped by manufacturers and distributors; or other non-dutiable commercial articles or informational materials that are not subject to resale.
(b) The merchandise items are related to the printed matter with which they are being mailed.
(c) The merchandise items are affixed to or are otherwise combined with the accompanying printed matter.
(d) The weight of each mailpiece or package that contains merchandise in combination with printed matter does not exceed 4 pounds.
(e) The M-bag containing merchandise items is accompanied by a fully completed PS Form 2976, Customs Declaration CN 22 - Sender's Declaration (green label).
e. Identification: PS Tag 158, M-bag Addressee Tag, must be completed and attached to the neck of the sack.
f. Postage: The applicable M-bag or International Surface Air Lift® (ISAL®) postage must be affixed to PS Tag 158.
g. Extra services: Certificate of mailing is available. Registry and insurance are not available.
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