The Mallory SRP255 Universal Flatted Shaft Volume Control is a replacement potentiometer component manufactured by P.R. Mallory & Co. for vintage electronic repair and radio restoration. Designed with a broad base measuring 1-3/4 inches in full diameter and a 1-1/4 inch shaft length, this control features a shaft configuration with a 1/2 inch round outer diameter and a 1/4 inch inner flat diameter for precise knob fitment and reliable resistance performance.