The Flow EX3 craves high speeds and the most demanding trails and courses. It's designed with increased stiffness without compromising its ride quality and ability to absorb impacts.Rim Durability - rim has internal reinforcements and thicker walls vs. the Flow MK3 and is built to take more abuseHub Durability - steel axle triple freehub bearings and reliable engagementBead Socket Technology (BST) is a patented rim shape that creates an advanced airtight system for tubeless bicycle rims and tires making an easier to use safer and more secure interface between the rim and tireFlow EX3 wheels include pre-installed tape for tubeless use and presta valvesThe rim's Tiebeam brace and patented low sidewalls of the Flow EX3 resist dents and air loss during impactsThe E-sync hub is built for strength and durability with chromoly axle double row Enduro bearings 6066 alloy shell and heat-treated steel ratchet ringBead Blasted "BBQ" finish for added durability