Made in the USA T50-2 Toroid Core MICROMETALS OD = .500 in / 12.7 mm +/- 0.02 in ID = .303 in / 7.70 mm +/- 0.02 in Ht = .190 in / 4.83 mm +/- 0.02 in AL=4.9 +/-5% 250 KHz - 10 MHz From bulk packaging, not in retail packaging.