r/Microcassette

Got this pretty-mint condition Lanier recorder. Can't really find the manual, so what are those two buttons on top of the unit?

If I press any of it while recording it just records silence. I thought one of them might be for index tone, but neither are making any kind of beep on fast forward. How to use it right?

My collection is also have some bigger ones ( not pictured )for regular cassettes and digital ones ( pictured )

Iv had this idea for a while and i need ur opinions a voice recorder travel trunk