Generally for the person who experiments with everything.
Custom Frequency Range (Extremely Adjustable).
This is guaranteed to work.
Wide Range of Adjustment.
169 Amp capability (changeable by request).
LED for observing frequency (Choice of green, red or blue).
Quality plastic box with rubber feet.
Warranty!

Upgrades:
Larger Heatsink
Split Ranges
Multiple Mosfets
Reverse Polarity

Note: These are not identical to the original Meyers or Lawton schematics. They are built much better and capable of much more amperage. Cases were surplus, but better quality than any other I have seen.