This next pic shows the main attachment for the drill or electric screwdriver that holds the quickchange drill bit, and one of the 3 combination countersink drill and philips screwdriver bits. The screwdriver bit is changeable to flat or square bits and it is magnetic. The drill bit is a special bit with a flat area on the shank to lock it into place. The #8 bit adjusts for depths of 5/8" to 1 7/16" by loosening a hex lock nut that locks onto the flat portion of the shank. The attachment that goes into the drill has the hex key built into the end of if, so you never have to look for a hex key to adjust your drill bit.
The next pic shows the bit holding attachment in the drill with the quick change piece with the counterdrill drill bit out, then with the screwdriver bit out. All you have to do is adjust the drill bit depth, drill the countersink hole, silp the piece out and reverse it to drill in the screw.
I broke off my #6 bit, but think I can use my grinder or a file to flatten an area on the shank of a regular bit that fits the piece, so that I can lock it in place.