1.375 inch diameter smooth rounded throttle knob to replace Van's standard knob. 1.375 inch diameter is the standard size. Material is UV resistant ASA plastic. Threaded insert pull out force is 1000 lb. The new knob runs true and spins concentric. Simply unscrew the standard knob and clean the super glue from the threads and screw on the new knob. Use a similar super glue thread lock and apply to the threads. No thread lock with acetone (the blue stuff). The green wicking thread lock is acceptable. Enjoy the new tactile feel of the printed throttle knob. This is what 3D printers were really made to do. You will never go back. This is for one new throttle knob in black or dark grey color. The small marks you see in the forward portion of the knob plastic are randomized printer knit lines.