Enclosed ferrite core for power cords. Great for cutting noise on USB, , phone, power cord, , audio, video cables, etc. Simple, convenient, effective and small. , high efficiency, long life. Put it closer to where the source is, the more effectively improve the signal of audio and video. Features - Color: Black. - Material: Nickel zinc ferrite. - Size: 17.80X10.00X2.30cm/7.00X3.93X0.90 inch. - It can improve the field around the solenoid, thus avoiding outside . - Ferrite core. Helps to reduce on power lines. - Easy to install and convenient to use. The cylinder can be dismountable, and the port has an elastic clip fastener. - This noise can be widely used on a variety of data cables. - It is manufactured with technology to ensure the of the product and can work for a long time. Package list: 22 x filters