• Adapter that enables you to make your steering tube longer whilst retaining the same stem system.
• BHP 20 is for 1" forks. BHP 21 is for 1 1/8" forks.
• Threaded and threadless headset compatible.
• Sandblasted black BBB RoundHead top cap included.
• Size: 28.6mm upper diameter (new stem mounting part) - 25.4mm lower diameter (bolts inside existing steerer)