Multi- aperture cores are used in suppression applications and in balun (balance- unbalance) and other broadband transformers.

Fair-Rite product number 2873000202.

Weight 3.7g
Length 14.35mm
Height 13.30mm
Holes 3.80mm
 
Ideal for use as a receive antenna transformer for a Loop on Ground antenna, see http://www.kk5jy.net/LoG/ for details.