most use 120 film to give 12 exposures of 6×6 negatives
some (eg. the Mat 24) use only 220 film to give 24 exposures of 6×6
the 44 uses only 127 film to give 4×4 negatives
the Mat 124 and Mat 124G allows either 120 or 220 film
most (?all) use a 80mm f/3.5 taking lens with a Copal shutter 1-1/500th sec and Bulb with M-X sync. No filter thread but a Rollei bayonet 1 mount for Yashica filters, lens hood or auxiliary lenses;
most have a self-timer BUT you must use this ONLY when the XM lever is in the X position
the later models use a f/2.8 viewing lens for brighter focusing with a 3x viewing loupe built-in
auxiliary lenses available via a bayonet lens mount to give wide angle (58mm), telephoto (113mm), macro 1 (40-65cm distance) or macro 2 (35-45cm distance).
The Yashicamat is basically a Rollei copy, with a few of the more expensive features left out, but the ergonometrics left in. Crank wind, combined film wind-shutter cock, Rollei bayonet 1 mount for filters;