Vintage Centralab (CRL) F1-15 Front Fastatch dual volume control base featuring a 2,500-ohm (2.5K) resistance rating with a C5 taper profile. Designed with a blue inner shaft for visual identification, this front-unit potentiometer integrates into concentric dual-control assemblies in vintage radio and audio equipment. Features a 15/16-inch control base diameter and a 3-1/2-inch overall shaft length. The dual-concentric shaft configuration utilizes a 1/4-inch outer shaft diameter paired with a 9/32-inch inner shaft diameter. Ideal for antique radio chassis restoration and dual-control replacement applications.