Gibraltar Black Ball Beater for Cajon and E-drums Black Ball Beater for Cajon and E-drums This Gibraltar Black Ball Beater features a felt tennis ball-style beater to provide a steady, protective low end for your cajon and e-drums Fixed on a steel rod with a fastening nut This Gibraltar Black Ball Beater features a felt tennis ball-style beater to provide a steady, protective low end for your cajon and e-drums Fixed on a steel rod with a fastening nut