Simple, molded-plastic "drop-in" module that replaces standard back of older bellows-type Polaroid cameras to allow use of still-available 120 and 220 type (non-instant) roll film. The purpose would be to make medium-format photography less expensive for the beginning "art" photographer. (Custom conversions of some older Polaroid cameras to large-format 4"x5" type film cost around $3000. New medioum-format cameras cost typically in the $1,000 range, even used, 20 year-old cameras in good condition can cost $300 or more.)-- whlanteigne, Sep 28 2002 This is precisely what I`ve been doing for years! the Polaroid models 110A and B, 110, 120, 150, 800 and 900 are all suitable!-- razzledog, May 11 2004 random, halfbakery