VKTRY VK BOOST: Take your VKs to the next level. The VK Boost is our proprietary technology in a booster strap designed to maximize energy return (estimated +25% more), improve athletic efficiency and reinforce ankle stability. A great addition to your VKTRY insoles, these simple booster straps are comfortable, discreet and easy to wear. Just wrap the VK Boost strap under your sports insoles, loop them up around the ankle and secure in place. The simple strap design can be added, removed and adjusted in seconds. Our booster straps for VKTRY insoles are dynamic sports tech ideal for serious and casual athletes, along with competitive and active people, and provide a performance boost to anyone looking to run faster or jump higher. Acting as a supportive ankle stabilizer and offering added protection for the ankle joint, the adjustable insole accessories are a great addition to the lower leg injury prevention already offered by your VKs. Our Founder Matt Arciuolo worked as the Certified Pedorthist for the USA Olympic Team for over 10 years. He invented VKs to help the team increase their explosiveness at the start of the race. His goal was to help the team win more gold medals – and they did! VK Boost insole straps are available in two sizes: Medium (Men's Size 9/Women's Size 10.5 and below); and Large (Men's Size 10/Women's size 11.5 and above). Up your game with the VK Boost!