Features: Helps reduce EMI on AC power lines. Black Plastic Enclosed Ferrite Core for 5mm AC Power Cables. Great for cutting noise on USB, firewire, phone, power cord, coaxial, audio, video cables, etc. This rectangular ferrite bead can be widely used in various data cables, USB cable, telephone line, network line to shield external electromagnetic interference. Easy to install with double clip; Reduce electromagnetic interference and improve signal integrity. Easy structure and convenient installation. Just clip it on and you'll get a clearer signal and faster data transmission. Warm Prompt: The element can effectively protect EMI and RFI interference. Please install them on site near the source of interference. (Near import and export protective casing as much as possible.)Specifications:Material: Ferrite Mn-ZnColor: Gray Size:Inner Diameter: 3/5/7/9/13mm. Quantity: 1 Pc Note: Please allow 1-3mm error due to manual measurement. Pls make sure you do not mind before you bid, due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! No Retail Package Content:1 x Ferrite Cable Clamp