It's a card that works kind of like a Debit card where you can use the card to withdraw money from the ATMs in Europe. However, the card is not linked to your bank account. Instead, before the trip, you will decide how much you want to deposit into the card (it's like pre-paid) and during your trip, you just withdraw whichever amount you want from this pre-determined amount that's linked to your card. You can also request to have and extra card thats linked to the same pool of money in case 1 card gets lost/robbed.
When you return to Singapore, you can cash out the remaining amount that's left in the card from Travelex Singapore branch. Yes there's a service fee however, I think it's worth it for the extra peace of mind.