Netflix gift card 15 euro?

I have a Netflix gift card of 15 euro if I get now the offer of 11 euro hole then the 4 euro away or I can transfer to the next month.

The credit, that is the 4 Euro, remain on your account. You can continue to use it the next time you load the credit.

The 11 euro of the 15 are quite normal 1 month and the 4 euro are so few days about 1-2 weeks or so