Material: Aluminium, black anodised finish, scale (version S) and arrow (version A): white, engraved with laser precision . Knob cover disk: light- grey plastic. Collet/hexagon nut: brass. Stainless steel set screw: DIN 916 with Allen screw and serrated end. Shape A: with arrow Shape B: neutral, without arrow or grading. Shape S: with scale 0...9, 20 graduations. Version 1: with set screw (bore d2). Version 2: with collet (bore d3). When mounting, the cover is pressed in by hand, for demounting it can be lifted up at the slot using a screwdriver. The collet version allows easy adjustment of the knobs and offers completely secure mounting on the shaft. Scale or arrow are fully abrasion proof and easy to read, as the engraving makes the aluminium coloured figures and numbers stand out against the black, anodised surface. Besides the standard scale (Version S) these knobs can be supplied with any scale desired (on request).