Features: Center lock adapter for mounting 6 volt brake disc adapters on center lock hub Compatible with 9mm / 12mm / 15mm hub axles High quality aluminum alloy construction, durable, corrosion resistant. For brake discs up to 203mm in diameter. Can be installed both front or back for replacement. Specifications: Material: Aluminum Alloy Color: Black Weight: 28g / 1.0oz Package Size: 10 * 7cm / 3.9 * 2.8in Package List: 1 * Center Lock