What do you mean by "Cashless Payment Wristbands?"

What do you mean by "Cashless Payment Wristbands?"

‚ÄčWe use a cashless payment system at Ultra Europe. Upon receiving your festival bracelet, you will have the possibility to top up your wristbands with money in order to be able to pay for drinks, food, and merchandise at the venue. Payments for top-ups can be made in cash money or through credit cards. Top-up stations will be available at the entrance and inside the venue. You can top up your wristband as many times as you want.