Ferrite binocular cores are wonderful for making many different
ratios of voltage baluns/ununs and magnetic baluns for balanced loads.
Typical ranges of ratios are 1:1 to 16:1. Our 9:1 beverage transformer
uses the BLN-68-61 core featured below. Shown in the picture below is a
1:1 current balun made with a BLN-61-61.