What Battery for Sinar Booster 1

Hello,
The title is the topic. Sinar Booster 1 with no instructions,no battery. The place for rhe battery is square.
Thanks,
Bill

Hi!
The battery type should be printed in the battery compartment (below the + symbol). Anyhow, it says: 4SR44, (4G13), 4LR44.
It's also called PX28.
You can find an instruction manual at The Sinar library

BTW, this message would probably be easier to find in the Large format cameras section.

//Björn