The Muse Flex is a series of twin-lens reflex (and perhaps some pseudo TLR) cameras for Bolta 35 mm paper-backed roll film, made by Tougodo from the late 1940s to some time in the 50s. At least some of the cameras are branded Muse Optical; McKeown states that this is simply a brand used by Tougodo. There are several models, with different levels of specification, some with 'I' and 'B' shutters and others with a reasonable range of shutter speeds. Nekosan states that the first camera in the series was the wooden-bodied Meikaiflex, but the Muse Flex models that followed it are metal bodied. He shows the instructions for the Muse Flex IIa, and describes this as the last and best model. The IIa at least is a true TLR, the viewing and taking lenses directly geared together for focusing. It has a KTS shutter with four speeds 1/25 - 1/150 second, plus 'B', synchronised with an ASA bayonet contact, and a f/3.8 Muse taking lens (perhaps a 50 mm; the leaflet is indistinct). The viewing hood has a focusing loupe.
- McKeown, James M. and Joan C. McKeown's Price Guide to Antique and Classic Cameras, 12th Edition, 2005-2006. USA, Centennial Photo Service, 2004. ISBN 0-931838-40-1 (hardcover). ISBN 0-931838-41-X (softcover). p705; a Muse Flex Model M is shown with a shutter engraved 'Complete', not 'Automatic' as is the example cited at Christie's.
- Muse Flex Model M, with an f/5.6 lens, flash-synchronised 'Automatic' 'I' and 'B' shutter, and no visible focusing control, sold at Christie's in London in May 2005.
- Bolta-size TLR cameras including the Meikaiflex and at least four different Muse Flex cameras, and the instruction leaflet for the Muse Flex IIa, at Nekosan's Nekogahora Camera Collection (archived).