Features:Great for car amps & battery terminals.use these to clean up the look in engine bay and amp connections.Works perfect with amplifiers that take a direct wire input. Much better connection than spade connectors. | Product name : insulated ferrule, model : e25-16, design : tube Type ,Material :plastic + Copper, color : black, red. | Plastic part Size : 10.5 x 11 x 11 mm / 0.41" x 0.43" x 0.43" (inner Diameter meter*od*l), total Length : 28 mm / 1.1". | Fit wire gauge : 4AWG 25mm2, tube Size : 7.5 x 8 x 16 mm / 0.3" x 0.32" x 0.64" (inner Diameter meter*od*l). | 100% Brand New High Quality Terminals Connector.