Olympus Recordata Back 2 till Olympus OM-system kamera.
Note the max date to use

The Recordata Back 2 has four data-presetting dials allowing the photographer to record information in numerical and alphabetical symbols directly onto the film.

Mounted on the OM body in place of the standard camera back, this unit is capable of recording information such as the year, month and day, or other numerical and alphabetical coding 7 digits max., directly in the lower right corner of the picture.
If you set any of the four dials at blank position, you can imprint on the other dial(s) only.
Dial 1 (right hand side) controls imprinting on the left side numbers (0..9) or alphabets (A..Z).
Dial 2 imprints numbers(1..15) or years (79..98) in the second position from the left.
Dials 3 and 4 imprint numbers (0..36) in the third and rightest position.
If no imprinting is required, set the Film Indicator to the OFF position and this unit can be used as a normal camera back
Film type can be set with the Film Indicator for 25..160 ASA, 200..400 ASA and a special setting ">" for films indicated by a chart printed on the inside of the Recordata Back 2.
It is capable of printing on colour and B&W films.
Imprinting can be checked by a red LED.This unit is powered by two 1.5V batteries (SR44 or LR44).
The Synchro Plug connects to the Synchro Socket of the OM body. With the OM-1 or OM-2, the Synchro Flash Selector should be set to 'FP':
1) when no electronic flash is used
2) when the Motor Drive is used in Sequential Mode.

This unit is powered by two 1.5V batteries (SR44 or LR44).
The Synchro Plug connects to the Synchro Socket of the OM body. With the OM-1 or OM-2, the Synchro Flash Selector should be set to 'FP':
1) when no electronic flash is used
2) when the Motor Drive is used in Sequential Mode.