This is the shimano slx rt68 ice tech centre lock disc rotor gives excellent performance using the proven shimano centre lock system providing excellent rigidity and security with an easy set up 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 improvem