Specification: Color: black Inner hole diameter: 3.5mm，5mm，7mm，9mm，13mm； suitable for 3.5-13mm diameter of wire Feature: The inner hole buckle is elastic. You can put the harness on top of the fixed ring. It doesn't cause distortion of the transmitted signal and won't affect your audio, video and picture quality. Good high-frequency noise suppression. Easy structure and convenient installtion.  Can improve the electromagnetic field around the solenoid, avoiding outside interference. Can improve the signal quality and shield radiation. Used to house all kinds of wire such as: the power cord, audio cable, AV cable, data cable. Package included:  20pcs x Ferrite Filter