Can you give me a link to the 50V 4.2A stepper driver? The price is always difficult to set but I thought I set the price lower than any other A3977 based stepper driver I could find...in the U.S. at least. Also yes those are absolute maximum values straight from the datasheet, and that's a great idea I'll add recommended voltages and currents. The heatsinks I talk about on the front of NorDevX.com which I'm going to do some tests with. Without a heatsink you really shouldn't go over 1A at the moment.