Let me start with what is NOT a mechanical mod. Anything with a display is not mechanical, you pick a voltage, or a wattage, or on some devices, a temperature, and the device converts battery power to whatever you selected. On mechanical mod, there is no chip to figure any of that out, just a battery, a metal tube, an atomizer, and a button that connects the circuit. So whatever the battery supplies in voltage is what will be supplied to the coils.