Double wedge system attaches the adaptor to the fork. Extra long bolt preloads the headset bearing, using the original star nut in the fork. 6061 aluminium alloy.
If you want to use one of these adaptors, be prepared to replace any (or all) gear and brake cables that are not long enough to reach the new, higher lever position. Requires minimum of 34mm steerer tube insertion. Also a maximum of 42mm: use spacers if more steerer tube is available. Weight: 214g.