Battery A21PX 523 EN133A PC133A PX21 1306AP TR133A for Digitech GSP-21 BRAND NEW - 1 YEAR WARRANTY FREE REPLACEMENT Aftermarket Replacement 4.5V Alkaline Battery 523 EN133A PC133A PX21 1306AP Battery A21PX 523 EN133A PC133A PX21 1306AP TR133A for Digitech GSP-21 4.5V replacement photographic battery Fresh - Free Shipping