MUQZI mountain road bike barrel axle hub conversion hub $ 9.90 uper accessory for your bike. Characteristics: Made of aluminum alloy, super light and resistant. Convert the 12mm hub to a standard 9mm hub. Supplied with 4 rubber O-rings. Tool-free installation, simply insert the adapter into the hub of the thru axle. Specifications: Material: Aluminum alloy Length: 142mm / 148mm (optional) Color: black / red (optional)