For the C64, C128 (in 40-column mode), and VIC-20, the BackBit cartridge is still for sale at

https://www.backbit.io/

See Evie's introduction to the BackBit at

https://www.youtube.com/watch?list=PLik3CBZlL5eW3O-LaLSmVX5k3eL0nKWet&v=G3t2_iloGVQ&feature=emb_logo

and how to use the BackBit at

https://www.youtube.com/watch?v=8YKruh_DiEY&list=PLik3CBZlL5eW3O-LaLSmVX5k3eL0nKWet&index=2

The big selling point of the cartridge is its compatibility with various disk, tape, and cartridge images, like D64, D81, CRT, PRG, P00, .20, .40, .60, .a0, and more. Just drop the image(s) onto a microSD card and pop the card into the
BackBit. You see
the file(s) on a menu, you select the one you want, and it loads and runs. No Commodore calisthenics to get the computer to recognize the image type.

As mentioned above, the BackBit cartridge works with the VIC-20 with a special adapter that fits the BackBit into the adapter. Evie has a video that explains
it at

https://www.youtube.com/watch?v=Une9mquKL0w&list=PLik3CBZlL5eW3O-LaLSmVX5k3eL0nKWet&index=7

For an independent review of the BackBit, go to

https://enragedgeeks.blogspot.com/2020/01/normal-0-false-false-false-en-us-x-none.html

Writing from Sydney, Australia, at the moment,
Robert Bernardo
Fresno Commodore User Group - http://www.dickestel.com/fcug.htm
April 25-26 Commodore Los Angeles Super Show -
http://www.portcommodore.com/class

P.S. Evie Salomon is tentatively scheduled to appear at the April 25-26 Commodore Los Angeles Super Show.

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