Beste antwoord door Momo
I see this here https://www.ns.nl/en/season-tickets/altijd-voordeel.html
The yearly subscription costs €24 per month and the one for only one month costs €28 per month. If you choose for one month (€28) it expires at the end of that month, If you need it for 4 months you will need to buy it again for the other 3 months.
After ordering it you will need to pick up the order at at machine.