mechanism. The circular tray also enabled the projector to display automated shows without the need to manually reset the slide tray between performances. Kodak also offered a stack loader that allowed running a stack of up to 40 slides without using a tray, but forward only; and clip sets holding up to 36 slides per clip. A box of 12 clips could store up to 432 slides, and keep them organized. During the 1970s, Kodak also produced a Pocket Carousel projector for use with miniature 110 format Kodachrome and Ektachrome slides. The Kodak Carousel projector was discontinued in October 2004. Vertical carousel variants Less well-known but plentiful is a family of projectors based around a design originated by Sawyer's and later sold under other brand names. That manufacturer's first slide projectors, in the late 1950s, had used straight trays. In 1963, Sawyer's Rotomatic, the first version using circular trays (called Rototrays), was introduced. These are distinguished from Kodak Carousel projectors by the round tray being in an upright orientation, like a Ferris wheel. Unlike the Carousel tray's use of a locking collar to hold the slide in the tray, the Rototray held slides in place using friction and a metal spring against the side of each slide. Projectors using the 100-slide Rototray were backward-compatible with the Bell & Howell TDC-Universal straight slide trays that had been popular since the late 1950s. The 1960s would also see the introduction of a plethora of less popular tray designs, most incompatible with each other, introduced by manufacturers possibly hoping to profit from the razor-and-blades business model. Nomenclature and history The first Kodak Carousel projector was targeted toward the consumer and carried the model designation '550'. In 1963, the first professionally oriented model was marketed in Germany as the Model S. Other models include: 1964–72: Carousel 800 (consumer) 1967–69: Ektagraphic (professional) 1969–71: Ektagraphic AF, E, and B (professional) 1971–84: Ektagraphic E-2, B2, F-2, AF-3 (professional) 1972–81: Carousel 'H' (models 600H, 650H, 750H, 760H, 850H, consumer) 1975–84: Ektagraphic AF-2K, AF-1 1979–84: Ektagraphic B-2AR, S-AV 1020, 1030, 2000, 2030, 2050 1981–2004: Carousel 4000, 4200, 4400, 4600, 5200, 5400, 5600 1981–2004: Ektagraphic III (E plus, A, AMT, ATS, Br, ABR) 1992–2004: Ektapro (320, 3000, 9020) 1992–2004: Ektalite (1000, 1500, 2000) The manufacturing date may be decoded using the CAMEROSITY code, which is a four or six-letter code which corresponds to the month and year (four-letter) or month,