SHIMANO Deore XT / ULTEGRA RT-MT800 CenterLock Rotor
Material: Strainless Steel, Aluminium
Weight: 88g (140 mm), 109g (160 mm), 132g (180 mm), 164g (203 mm)
External lockrings are mostly needed on 15mm axle bikes
Internal lockrings are for 12mm thru axles.