How do you meet your Kickstarter goal in two days? Offer people a backup smartphone battery that also fits in a wallet, that’s how. The TravelCard ($40), which is the backup battery we’ve so sorely needed, is made of aluminium, holds enough juice to let you talk for five hours, and fits easily in your credit card slot. It also comes in two versions: an iPhone 5 and 5S compatible one, and an Android one. So the next time you’re stuck in the desert, at least you’ll be able to livetweet it.