I am using some #31 material doughnuts which are 1.25"D x 0.25" H  with an ID of 0.625".  That 5/8" ID is just large enough for a USB connector to pass through allowing me to make a couple of turns of the cable through the doughnut.

Also, I've used some of the clamp-on types typically used for RG-8.  With these I can loop two turns through the ferrite.  As to the material, these are hamfest types, otherwise no clue.    The ones for RG-8X are not large enough to pass two turns.

73

Bob, K4TAX