25 Ohm Linear wirewound potentiometer by Spectrol. Series: 535 Bushed 1.5 Watts Turns: 5 Linearity ± 0.25 % Shaft 1/4 inch ( 6.35mm) x 0.47 inch (12mm) Download Spectrol 535 series .pdf datasheet: Status: NOS (New Old Stock) Original Spectrol, not later Spectrol Vishay. Supplied complete with locknut and washer. RoHS compliant: not known.