Mar 18, 2015 Addressing "Slippage..." We've been fielding a lot of questions about Ninja Sox staying on your feet. We understand that the previous version (2.0s) weren't the best design for everyone...we tried to accommodate the majority of you, however it might not have worked out as planned. HOWEVER, we believe the 3.0s are much better at staying on your heel as well as overall comfort. You'll notice it is a complete redesign of the socks and our initial customers have loved the 3.0s. In addition, we package each sock individually so that you can try out 1 pair at a time. If it doesn't work out, please reach out to us (firstname.lastname@example.org) and we'll work out a return. With that being said, for a limited time, we'll offer a money back guarantee on the 3.0s. You can return any unopened pair of socks for a full refund on the price of the socks (minus shipping fees). We hope that helps your decision to try out Ninja Sox. Thanks, The Ninja Sox team!