Finnair Excess baggage
If you are travelling with baggage that exceeds your baggage allowance, an extra bag charge applies. Each fee is for flights in one direction. You can use your Finnair Plus points to excess baggage charges. The amount of Plus points needed depends on whether you travel in Finland, Europe or on a loung-haul flight. Excess baggage voucher is valid for one way on Finnair flights (Finnair or Flybe aircraft and AY code on the ticket).
More information available here.