Flange Coupling High-strength aluminum alloy Omni wheel diameter five 6 eight 10mm 12 14 15 16 18 mm keyway couplingMaterial: aluminum alloySurface treatment: anodic oxidationNote: There are 3 via holes with a diameter of 5mm disbursed on a circle with a diameter of 47.5mm, that are used to install normal 100~152mm wheat wheels and common wheels on the market.Three via holes with a diameter of 5mm are dispensed above the circle with a diameter of 45mm, which is well suited with a wheat wheel with a diameter of 152mm.Standard sizes: