This item is a 3 1/4" Wide 6 Spoke Graphite Gray Knob for 1" Air Control Valve Knob.
The outside measurement is about 3 1/4" and the center hole is about 5/16"..
NOTE: There is a Waterfall Control version of this knob that measures about 3 5/8" wide with a center square that is about 1/2" wide. This cap and that cap are not interchangable..
