Mini-Kits stock a range of Micrometals brand Powdered Iron Toroidal cores that are commonly used for RF filters resonant circuits, and Antenna matching transformers.  Unfortunately due to the lack of distributors selling into Australia, we can no longer easily obtain these products in reasonable quantities so they will be discontinued over time.  We have had to restrict maximum quantities available to prolong the stock that we have, to be able to support Kits that are still being produced.