This (single) Phenolic Pointer Knob, measures 15/16 inch Diameter 3/4 inch High, and is made for a 1/4 inch Shaft. It has a slotted set screw.It can be used on several types of electronic gear including new and vintage Radio gear, Audio equipment, Guitar Amplifiers and anything that has a 1/4 inch shaft and requires a pointer knob.( also offer sets of 8 and 16 at a discount!)I am very pleased to offer this new Grade A Plenco Phenolic, original knob for a great low price! You will be very surprised when you see what a difference it will make to replace the old pointer knobs that have lost their shine and have yellowed lines rather than nice bright white lines they had when new.