The Tour Kemistry Cyclonium Wheels are the very science behind roller hockey. At 72mm these are perfect for entry level skaters looking for a softer indoor wheel. With a 78A durometer, this soft wheel creates the perfect relationship between you and the floor for ultimate grip and performance. Extreme Grip - Elite-level grip to deliver speed and power. 78A Durometer - Soft wheels for high-performance surface contact. Made in the USA - Designed in California with exacting quality standards.