Freesat from Sky cards, or free to view cards, are cards to unlock some UK TV channels on a Sky box. These channels are classed as "free to view" channels. They require no monthly subscription, but do require a Sky card.

These cards are called Freesat From Sky (FSFS) cards.
They are incorrectly known as "Sky Freesat" cards, or "Freeview" cards. No card is required for "Freeview" channels, and you cannot receive Freeview in Spain anyway!

A Freesatfromsky card unblocks the following channels on a Sky set top box.

Some ITV1 regions on frequency 11973 v
Some ITV1 regions on frequency 12402 v
Irish Channel 4 region on frequency 12480 v.
Five, Fiver (now 5*), Five USA and their "+1" timeshift channels - Sky channel 105, 174, 175, 176, 177
Five HD - Sky HD channel 105 or Sky HD channel 171
Pick TV (formerly Sky Three) and the "+1" timeshift channel - Sky channel 152, 153
Sony TV - Sky channel 157
Viva TV - Sky channel 357
Motors TV - Sky channel 413
Liverpool FC TV - Sky channel 434

Reception of these free to view channels may depend on your location, dish size, and receiver.