Jack Dorsey's little credit card machine that could only really had one major flaw: it only worked with an internet connection. That's not an issue any more, thanks to an update to the Square Register iOS app which now lets you accept payments offline, as long as you upload them within 72 hours. You can set a limit on the value of each transaction, automatically set yo $100, since you'll lose out on any declined sales that weren't verified at the time. Still, if you trust your customers and have spotty WiFi, then it's probably worth checking out.