Made of Metal not Plastic Push on fit knobs without set screw Knobs only fit guitars or basses with metric 18 coarse splines split shaft pots with 58mm diameter they DO NOT fit USA 24 fine splines split shaft pots as well as any other Solid shaft pots In order to get correct knobs for your pots please remove the current knobs from your guitar count the splines on your pots if they are 10 on each side your pots will need 24 fine spines knobs if they are 8 one each side your pots will need 18 Coarse splines knobs Please see our photos for reference Please confirm the diameter of your guitarbass pots before you order the item See more product details