S1A and a canopy over both cockpits. 4-DM Senior Speedmail (ATC 326) Single seat mailplane version of the 4-D. Two built, both converted from other models. 4-E/C4W Junior Speedmail (ATC 292) Pratt & Whitney C-1 Wasp or Pratt & Whitney Wasp 11 built. 4-EX Senior Speedmail (ATC 2-279) One customized 4-E built for Standard Oil with a Pratt & Whitney Wasp SC. 4-EM Senior Speedmail (ATC 322) Single seat mailplane version of the 4-E. 4-RM Special (no ATC issued) One 4-CM was converted into a four seater and powered by a Ranger GV-770. Model 80 Sportster (ATC 504) 1933 one-off custom two-seater with dual controls and an enclosed canopy for the rear cockpit, with a Pratt & Whitney Wasp Junior T3A engine. Model 81 (ATC 504) One built as a trainer variant of the 80 with enclosed canopy over both cockpits. Sold to the Mexican government after a tour of South America while on floats. Operators Canadian Airways - 4 Northern Airways American Airlines Department of Commerce Airways branch (4-C) Fenstra Steel (4-C) Pratt & Whitney (4-D) Richfield Oil Company Texaco (4-D as number 14) Varney Air Lines Western Air Express (4-D) Survivors c/n 4005 4-E Junior Speedmail N663K - privately owned, in National Air Tour markings. c/n 4007 4-E Junior Speedmail NC667K - delivered in 1929 to the Richfield Oil Company as the "Jimmie Allen Flying Club" flagship and used until 1937. Following a 2007 restoration, it flies on the North American air show circuit and in 2013 won the Sun 'n Fun Grand Champion - Antique award. c/n 4021 4-EM Senior Speedmail CF-AMB - displayed at the Canada Aviation and Space Museum in Ottawa, Ontario. c/n 4022 4-CM Junior Speedmail NC785H - privately owned, flown in Standard Oil Stanavo colors. c/n 4025 4-D Junior Speedmail NC774H - privately owned, flown in Western Air Express colors. c/n 4026 4-E Junior Speedmail N11224 - displayed at the Yanks Air Museum in Chino, California. c/n 4027 4-D Junior Speedmail N563Y - displayed at the Kansas Aviation Museum in Wichita, Kansas in Texaco markings. c/n 4033 4-DM Senior Speedmail NC485W - built as a 4-CM and re-engined, privately owned, flown in American Airways colors. c/n 4036 4-CM-1 Senior Speedmail - NC488W privately owned, flown in Standard Oil Stanavo colors. c/n 4037 4-CM-1 Junior Speedmail NC489W - privately owned, flown in Standard Oil Stanavo colors. c/n 4040 4-C Junior Speedmail N11722 - privately