Originally Posted by kalnaren
They cost between $70-$100/ea and require quite a bit of soldering work to install.
When I say "MOSFET" I mean the $20-$30 switch, SW-COMPs are the computerized ones
Some gunsmiths have spools of high quality wire if you want to buy a few feet, RC hobby shops should have high quality silver plated copper wire though. 18 gauge will be good for an M4, but the rule of thumb is to use the thickest gauge possible.