Black plastic knob for 6mm shaft with raised black face, serrated circumference and raised white pointer line down one side. 0.50" diameter x 0.60" high. Brass insert and set screw. Also available with blue (CAT# KNB-267BL), green (CAT# KNB-267GN), red (CAT# KNB-267RD) and yellow (CAT# KNB-267YL) faces.