Circular town mark at left, value figures in tombstone shaped box at right, all within greater border.
Two sub-groups exist. Sub-group GA stamps were printed by the "JD" and "JDC" models which were versions of the "J" and "JC" meters (see Group F) modified to allow the town mark dies to be easily toggled on or out from the stamp. Earliest known use of a GA stamp is April 4, 1936.
Sub-group GB stamps were experimental designs produced by trials of what would become the "RS" mailing machine and the "RT" meter. The "R" series was similar to the "J" series but much faster. (After these trials the "R" series machines were used for the long-lived Group I stamps introduced in 1940.) Earliest known use of a GB stamp is July 13, 1938.
"U.S. POSTAGE" curved above "PAID" inside tombstone shaped value box at right.
Meter number appears at bottom center below "P.B.METER".
Meter numbers: 91000-93999 and 95000-98000. (Meters in the 94000 series were used in Canada except for machines 94500, 94501 and 94502 which were used in the Philippines.
Earliest known use is April 4, 1936.
GA1. Models "JD" and "JDC" (multi-value), April 4, 1936.
V/F: 0 00 (range: 0 01 to 99 99)
a. With "REGISTERED / MAIL" slug at left
GA2. Models "JD" and "JDC" (multi-value).
As GA1 but with different value figures.
V/F: . 00 :(range: .00½ to 9.99½)
a. With "PERMIT (number)" at left
b. With "PERMIT NO. (number) at left: 92600 (228), 92660 (219), 95295 (219) seen
c. With "P— (number)" at base of town mark
d. With hour slug in vertical lines at left
e. As d but hour slug removed leaving only the vertical lines: 91463, 92735, 96259
f. With "REGISTERED / NO" at left (See also Type FB2.1.)
g. With "REGISTERED / MAIL" at left
h. With "INSURED" at left: 92745
j. With "INSURED No." at left: 93923
k. With town name and state inverted, date upright: 93374, 95502
l. Without meter number and with "U.S." of "U.S. POSTAGE" missing: "TWIN FALLS / IDAHO" (This is possibly a contrivance engineered unofficially by a Pitney Bowes shop employee.)
m. With small ornaments in the town mark
n. With "SPECIAL DELIVERY" at left
SURCHARGES:
-1. "AD'L ⅛¢ PD." at left: 93030 [RRRR]
-2. "AD'L ¼¢ PD." at left: 93030, 95911, 96644 [RR]
-3. "AD'L ⅜¢ PD." at left: 92981 [RRRR]
-4. "AD'L 0.8¢ PD." at left: 96509 [RRRR]
-5. "Additional Postage at Third Class Rate Paid for Enclosures (town name) Permit No. (number)" at left: 95171, 96586 [R]
Stamp designs used in trials of experimental high speed multi-value "RS" mailing machine and "RT" meter.
Meter numbers: X1003-X1005, 100000, 100003, 100006-7, 100011-13.
Earliest known use is April 4, 1936.
Type GB1 in 2001 edition
GB1.1. Model "RT" (multi-value), July 13, 1938.
Similar to Sub-group GA stamps but the tombstone value box is taller with "U.S.POSTAGE" fitted into the arc at top and with "PAID" at bottom. Frank 51 mm wide.
"P.B.METER" is larger.
The town mark is closer to the top of the frank rather than the bottom.
Three stars above eagle's head.
A. Meter X1003 used by Prentice Hall of New York [RR as tape or piece, RRRR on cover]
B. Meter X1004 used by the Federal Reserve Bank of New York with hour slug at left [R as tape or piece, RRR on cover]
C. Meter X1004 used by Pitney Bowes in Stamford CT [RRRR]
Used for nine months between July 1938 and February 1939.
V/F: 0 00 :(range: 0 00½ to 9 99½)
Type GB2 in 2001 edition
GB1.2. Model "RT" (multi-value). [RR as tape or piece, RRRR on cover]
As Type GB1.1 but the town mark is closer to the bottom of the frank rather than the top.
"P.B.METER" is much smaller.
Meter X-1005 used by Yale & Towne of Stamford CT for nine months between July 1938 and February 1939. Both the Yale & Towne building and the meter were destroyed in a fire.
V/F: 00:(range: 00½ to 99½)
Type GB3 in 2001 edition
GB2.1. Model "RT" (multi-value), January 11, 1939.
At 50 mm the frank is slightly narrower than Types GB1.1 and GB1.2.
"U.S. POSTAGE" is in a curved scroll above the value box rther that within it.
No stars above the eagle's head.
"P.B.METER" and meter number is in an elongated oval below the eagle.
A. Meter 100000 used by the American Chicle Company in Long Island City NY [RR]
B. Meter 100003 used by five different firms in three cities [R]
C. Meter 100006 used by several companies in New York [R]
D. Meter 100011 used by the Bank of the Manhattan Company in New York [RRRR]
All these machines were used for one year from January 1939 to January 1940.
V/F oval with serifs: .00:(range: .00½ to 9.99½)
NOTES:
Proofs from meter 100007 exist, but no postally used examples are known. [RR]
Meter 100000 is known with town mark STAMFORD CONN. with November 22, 1938 date. It is assumed to be a pre-test proof.
Two of the five companies that used meter 100003 are the Mathieson Alkali Works of New York and the Loose-Wiles Biscuit Company of Long Island City NY.
At least five different companies are known to have used meter 100006. They are Peter A. Frasse & Co., Columbia Broadcasting System, The Bank of the Manhattan Co., International Illustrated News, and The Hills Brothers Co.
Stamps of this appearance but with meter numbers in the 51000 series are from self-service "Mailomat" machines. See Group PV for these stamps.
Type GB4 in 2001 edition
GB2.2. Model "RT" (multi-value), October 10, 1939.
Very similar to Type GB2.1 but the Value Figures are smaller and sanserif.
A. Meter 100012 used by The Mathieson Alkali Works in New York [R]
B. Meter 100013 used by the Schick Shaver Co. of Stamford CT [R]
V/F: .00:(range: .00½ to 9.99½)
a. With hour slug slug at left: 100012 [RR]
NOTE: Stamps of this appearance but with meter numbers in the 51000 series are from self-service "Mailomat" machines. See Group PV for these stamps.
0 00 
(range: 0 01 to 99 99)
[RR as tape or piece, RRRR on cover]
