If the steerer tube is long enough , I like BBB's BHP 21 its a quill going inside the steerer, (probably not for CF steerers, mine is steel )
and the quill expander bolt is internally threaded, so after tightening the quill, the cap bolt threads into the top end of the expander bolt.
includes a number of keyed shim spacers to add height to a too short steerer, or you can put its whole length inside the steerer, except for really short frames..