Elma (020-5520) – Round Shaft Knob, 6.35mm
The Elma 020-5520 is a black round knob made of nylon (polyamide) with a glossy finish. It has a 28mm knob diameter — the largest in the Classic Collet range — and is designed for a 6.35mm round shaft, fixed onto the shaft using the proven collet tightening method.
Quick spec sheet: