these cameras included both folding slrs and less expensive nonfolding models. they take the sx-70 film, a format with a ~3.1 x 3.1 in² (77 x 77 mm) square image area and a ~4.2 x 3.5 in² (108 x 88 mm²) total area, and a sensitivity around iso 160. they come with a built-in 6-volt zinc chloride "polapulse" battery pack, replaced with a lithium-ion pack in polaroid original remakes.