Confirmed these are good belts with smaller sizes great for mid school and twin decks.
https://www.ebay.com.au/itm/Rubber-belt-cassette-recorder-repair-maintenance-repair-replacement-1-F-S-F/182947855505
https://www.ebay.com.au/itm/Rubber-belt-cassette-recorder-repair-maintenance-repair-replacement-1-F-S-F/182947855505