As described right from Rollerblade.com:

SHELL: Molded polyurethane, sculpted "flex" buckle protector, integrated power-strap, double-thick toe protection box, backslide groove for riding on rails, reinforced alley-oop fin heel for negative grinds, metal buckle and locking receiver, molded eyelet protection.

Liner: Speed lace liner system, textured micro-pyramid material for better adhesion to shell. Cool Max lining material for breathability and dryness, super-thick memory foam for extra comfort, leather cuff and tongue lining for durability, shock-absorbing insole, lasted construction for superior fit.

Frame: Super low profile, integrated Tri-piston shell interlock design, molded wings for sole protection, pre-grooved frame, and aluminum "H" block.

Wheels & Bearings: 55mm mounted to ABEC 5 bearings with aluminum bearing spacer

Available in sizes : 6-14.