Fair-Rite 5943003801 MnZn Ferrite Toroid, 43 material, for EMI suppression between 20 and 250MHz, and wideband transformers up to 50MHz.  ui=800.  These are ideal for use as noise or common mode suppressors on cables to reduce interference on the HF bands, or constructing baluns.  These are recommended for use on HDMI cables where the cable connects to the computer video card to suppress noise in the 3 to 20MHz bands.

Size: Diameter 61mm, Height 12.55mm Hole Size 36mm, color Grey, Fair-Rite PN# 5943003801

See W1CG Low Power Balun Manual for more information on making a 4:1 Balun.