The Revision Flex is an indoor wheel available in 80mm and 76mm in X-Soft, Soft, or Firm hardness. The Flex is like nothing currently offered on the market today - each wheel has a grippy, softer edge and a stiffer, faster edge. This allows for a player to 'fine-tune' their setup from Maximum Grip, to Maximum speed and everything in between. To better explain the idea and technology, here are the inventor, Neal Piper's words: “FLEX Technology is the next generation of the patented hollow torus wheel design system. FLEX takes three major steps forward and adds (1) an asymmetric “soft insert band” layer in between (2) an offset patented hollow torus. Then FLEX uses (3) a brand new super-tough PU tire compound designed specifically to last longer with our new FLEX technology. ALL NEW FOR THE 4-COMPONENT FLEX TECHNOLOGY Asymmetric Soft Insert Band Offset Patented Hollow Torus All New Super-Tough Long lasting FLEX Tire PU Speed Vs Grip: Note the SPEED vs GRIP photo. As the “SPEED” side of the wheel is loaded, there is a smaller contact patch and lesser conformance to the flat skating-surface. For the opposite “GRIP” side of the same wheel when equally loaded, the very unique asymmetric structure now allows for a larger contact patch and increased conformance to the flat skating-surface. The FLEX wheel clearly has two distinct performance personalities, now in only one wheel structure. Revision FLEX Wheel is the first and only asymmetric, fully micro-tunable wheel system on the market today. FLEX wheels will deliver the exact performance set-up for any weight and skating style. Try your set today.” Details: Made in the USA Sizes: 80mm / 76mm Hardnesses: X-Soft, Soft, Firm X-Soft - 72A/74A - Under 150lbs (Or players who want MAXIMUM grip) Soft - 74A/76A - Under 170lbs Firm - 76A/78A - Over 170lbs (Or players who want MAXIMUM speed) Weight: 95g