These are small ferrite beads secured on a wire link, to increase the inductance impedance at high frequency of wire link ,on which they are threaded. Ferrite type: 16, K.
100Pcs 3.5x4.7x0.8mm Axial Ferrite Bead Inductor Bead Ferrous Filter Core Coil
5/7/9/11/13mm Clip-on Ferrite Ring Core Ferrite Bead Choke EMI Filter Cable Clip
10x 3.5x5x1.2mm Ferrite Sleeve Core Ferrite Bead RF PA Choke decoupling
Clip-on Ferrite Ring Core Ferrite Bead Choke EMI Filter Cable Clip 3mm - 13mm
10 Qty 5x6x2.5mm Ferrite Sleeve Core Ferrite Bead RF PA Choke UK Seller
