Zoom Q-2 & Q-5 are cold forged and allow a 23mm height adjustment.
Cold-forged aluminum, 23mm height adjustment
Steerer Clamp OD 25.4mm, for 1", 28.6mm for 1-1/8
For installing threadless stems on a threaded fork
Quill Insertion Diameter: 25.4mm for 1 1/8" stems and 22.2 for 1" stems