A micro ferrite toroid for the QRP operator - this is perfect for small Baluns/Chokes and End-Fed Couplers. Ideal for use with low-power radios like the FT-817/818, IC-705, KX2, KX3 and similar.
For a simple QRP Choke Balun, use 8 bifilar turns of enameled copper or insulated wire. If being used across a wide SWR range, maximum power should not exceed 25-watts.
Toroid sizes/types are easy to ID, the "68" translates to 0.68" (diameter) and the "43" is the ferrite mixture. What type do you need? 43 is good from 7MHz and up (and a good general-purpose 7-30MHz solution) while 31 is good for lower HF bands. Remember, you can stack the cores for increased choking and power-handling. As always, ratings need to factor in the aerial (SWR) match and duty-cycle.