Unibody construction eliminates traditional lasting board to deliver super low 5mm stack height for maximum pedaling efficiency Advanced 3-Layer Seamless Composite Upper offers exceptional breathability and eliminates hot spots by adapting to your unique foot shape Bi-directional Closure wraps the foot for a semi-custom fit and secure foot retention; Replaceable heel bumper Boa IP1 reels allow 1mm micro-adjustability and pop up for full release; Weight: 240g (size 40) 1:1 Integrated Carbon Power Plate delivers feather-light stiffness (stiffness rating of 13)