M64P501KB40 Trimmer Potentiometer, 500 ohm, 23 Turns, Through Hole. The Model 64 is a small size trimmer – 3/8″ x 3×8″ x 3/16″ – answering PC board mounting requirements. Five versions are available which differ by the position of the control screw in relation to the PC board plane and by the spacing of the terminals. Excellent operational stability is provided by the use of a cermet element.