XTR/Dura Ace level RT-CL900 Ice Tech rotors providing consistent braking performance through energy control using revolutionary stainless steel / alloy 3-layer sandwich construction that manages heat while riding The clad steel / alloy / steel rotor construction allows heat generated from braking to radiate quickly through the aluminium core achieving surface temperature drops of around 50 deg C. When used with Ice Tech pads surface temperatures can drop from around 400 to 300 deg C this provides great improvements in performance all round FREEZA rotors allow the alloy core to extend out from the braking surface as a fin to providing added cooling Ice Tech rotors achieve long pad life less noise and less fade due to improved heat dispersion Rotors are durable lightweight and rigid using the proven Shimano Center Lock system giving increased strength and security with an easy set-up Precision cut braking surface improves pad clearing in muddy conditions while aiding cooling under high load Large alloy spider is a highly rigid and lightweight support for the rotor surface Super polished braking surface gives excellent braking performance Rotors come in sizing 203mm 180mm 160 and 140mm lockring spline options are available either internal external or internal with integrated magnet depending on the application required