15mm equidistant spacing between the To220 mounting holes - fits lovely onto most old PC CPU heatsinks. Conductive fixing holes on each end are 4.2mm diameter within exposed 10mm pads. Soldermask removed so you can solder real copper wires on to bolster the current carrying capacity. 1mm pullback/pad clearance throughout. All gates commoned together - but easily possibile to use a razor to split out into two fet pairs or even four individual ones. You can’t daisy chain these pcb’s directly together edge to edge with bolts (for example to get 8/12/16 fet combinations) - but could be a great timesaver if you just need to keep swapping banks of blown fets out!!! Tested in the field. Enjoy!