ITEM NAME:5 pcs Newest Micro metals Amidon T37-2 Iron Powder Toroidal Core T-37-2 ToroidLJ 5 pcs Newest Micro metals Amidon T37-2 Iron Powder Toroidal Core T-37-2 ToroidLJ a.imagelink a:hover.imagelink {color:#60000;.Material: Carbonyl iron powder. 5xCarbonyl iron core. We will reply you ASAP. frequency characteristics. - The annular structure has a very low electromagnetic radiation shielding. - Has a high temperature characteristics.