IRWIN SpeedBor 6-Piece Drill Bit Set

IRWIN SpeedBor 6-Piece Drill Bit Set

So, if anybody is interested, sizes of the bits:
1/2", 5/8", 3/4", 7/8", 1".
The extender has a very short shank dwell. Start the hole without the extender, then switch up.
Otherwise you are going to have a bit of wander, even with the “speed tip”.