As the X3000 is discontinued along with the older style of coils I made my own replacement coils. To get a little more field strength from the coils and allow for the option of adding a ferrous core to the coil I wound a circular coil. Here is the final result of version 1.0.
The graph the testing results of using NF64 and the Original X3000 Plus (average maximum values over 5 measurements, 10Hz @ 5v).
Coils are now available for $299 + shipping per set. A set includes 4 coils with LED, 1 adapter, 4 cables, 4 ferrous core inserts. Each set is built to order and takes about a week.