Description: Nickel Zinc Ferrite Core Rings Kit: Noise-suppressing core rings can enhance the electromagnetic field around the solenoid, thereby avoiding external interference. Clip-On Clamp Core Rings: 3.5mm/5mm/7mm/9mm 4 Inner Diameter Sizes. Easy to install and use, can be disassembled, and features an elastic clip-on port. Features: Great performance, high efficiency, and long lifespan, effectively improving the signal quality of audio and video. The cable clamp will not cause distortion of the transmission signal nor affect video and images. Wide Application: Suitable for various types of electronic connecting wires, wiring harnesses, homes, air conditioners, computers, inverters, electric welding machines, power supplies, etc. Specification: Material: Ni-Zn Ferrite Package Size: Approx. 17.8x10x23 cm/7.01x3.94x9.06 inches Introduction: 3.5 mm / 0.14 inches (inner diameter): suitable for 0.06-0.14 inches / 1.5-3.5 mm cables; 5 mm / 0.2 inches (inner diameter): suitable for 0.14-0.2 inches / 3.5-5 mm cables. Usage: Car DVR, speaker cable, mouse cable, keyboard cable, USB cable, RS232 serial port camera cable, etc; 7 mm / 0.27 inches (inner diameter): suitable for 0.2-0.27 inches / 5-7 mm cables. Usage: AV cable, coaxial audio, power cable, serial IP camera, etc; 9 mm / 0.35 inches (inner diameter): suitable for 0.27-0.35 inches / 7-9 mm cables. Usage: HD Multimedia Interface-compatible cable, VGA cable, DVI cable, power cable, speaker cable, industrial cable, etc. Package Includes: 25 Pieces Clip-On Clamp Ferrite Core Rings Kit (7pcs 3.5mm/5pcs 5mm/8pcs 7mm/5pcs 9mm) Note: When the wire is too thin, you can twist the magnetic ring to achieve a secure effect.