Check the listing for details. 20 Pack Ferrite Toroid Cores Sets Transformer Inductor Coil Ring Black. Condition: New. Listed at 15.17 USD. Description:Squareness rate: 10; Bs: 400T; Br: 150mT; Tc: 120°C; : 13A/m; ρ: 4.9g/cm3; μi: 650-1000; Packing List: 20 x Toroids (4 Pieces For Each Size)Advantage: Ferrite cores are dense, homogeneous ceramic structures made by mixing iron oxide (NiZnFe2O4) with oxides of nickel, zinc. Have very high permeability and low losses, can work at high frequenciesInstruction: Used to suppress electromagnetic emissions by blocking low-frequency noise and absorbing high-frequency noise, avoiding interferenceApplication: Widely used in EMI/RFI filters, audio transformers, communications, control circuit equipment, LED lighting, automotive electronics, industrial control, etc.Description:Squareness rate: 10; Bs: 400T; Br: 150mT; Tc: 120°C; : 13A/m; ρ: 4.9g/cm3; μi: 650-1000; Packing List: 20 x Toroids (4 Pieces For Each Size)Advantage: Ferrite cores are dense, homogeneous ceramic structures made by mixing iron oxide (NiZnFe2O4) with oxides of nickel, zinc. Have very high permeability and low losses, can work at high frequenciesInstruction: Used to suppress electromagnetic emissions by blocking low-frequency noise and absorbing high-frequency noise, avoiding interferenceApplication: Widely used in EMI/RFI filters, audio transformers, communications, control circuit equipment, LED lighting, automotive electronics, industrial control, etc.