Dual position, 2 bolt.
Infinitly adjustable tilt. Oval internal hollow in the Kalloy style which saves gobs of weight. On one bike I hacked off a few inches off to leave 110mm insertion & saved weight over the OEM carbon SLK with indexed tilt that I could never get quite right.

...Oh, & now I can ride for hours in the drops or choose aero bars if I want to.