Thse are spot-on reproductions of the knobs used on the early steel guitars and the Combo 600, 800, and 850.  These are just like the originals: machined from solid brass, nicely knurled, chrome plated, and heavy as hell.
 
Note that there are two styles of Combo knobs: for split shaft pots and for solid shaft pots. The solid-shaft knobs have a slightly larger hole and a set screw to grip the shaft. Similarly, a split shaft knob will not fit a solid shaft pot as the hole is too small.
 
PLEASE NOTE: Knobs are priced individually.  If you want a pair, buy two.