FT37-43 Toroid Core FairRite Brand Wideband Transformers 5 - 400 MHz Power Transformers 0.5 - 30 MHz RFI Suppression 5 - 500 MHz AL=350 +/- 20 % O.D. = 0.375 in / 9.5 mm +/- 0.25 mm I.D. = 0.187 in. / 4.75 mm +/- 0.10 mm HT. = 0.125 in. / 3.3 mm +/- 0.25 mm From bulk packaging, not in retail packaging.