Here's what other sites are saying:
The myFC PowerTrekk Puck is the fuel pack used by myFC PowerTrekk to carry out the fuel-cell based charge. You simply insert a Puck into your myFC PowerTrekk and add a little water, then you can immediately use your myFC PowerTrekk to charge the battery in your USB device. Each Puck will provide more than 4 watt hours of energy, which provides about a full charge to a standard smartphone. myFC PowerTrekk Pucks are sold in 3-packs.
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