The driver module consists of twin Si06N03 N-Channel logic-level drive Si06N03 MOSFETS. The Si06N03 is rated at 85A drain current. The original control switch has 5 settings, each increasing the control D/C by 20%. The heat sink paste shown here is just about how it was applied at the factory. Aka haphazardly. If you buy one of these modules, take it apart and ensure the compound has been appropriately situated. The control switch has 5 discreet resistors w/ rotary switch, and the module converts the resistance into D/C to drive the MOSFETs. The driver module has a 5v regulator but still switches the MOSFETs using 12v. Rather than trying to figure out where to inject a 5v switching signal, I'll use a separate MOSFET module to control the heaters.