Internal Delrin bearing cup only Smooth, gaul-free operation Low profile design allows 360° of rotation Fits 20000, 20001, 21000, 21001, 99026 Internal Delrin Bearing Cup for 20000, 20001, 21000, 21001, 99025, 99026 Internal Delrin Bearing Cup provides smooth, gaul-free operation Low profile design allows 360° of rotation