The extension is to limit torque, it is almost impossible to show this demo on a regular 19mm bolt with very powerful impact unless you can find a stuck crank bolt which can be tough if you are using 1000ft-lbs impact guns. If you would like to see the weight comparison of sockets they are in this video: https://www.youtube.com/watch?v=SGbYcLobC3M .
Here is my homemade 19mm heavy crank pulley bolt impact socket from this video https://www.youtube.com/watch?v=4c5uNnggwZU works great…but sometimes doesn’t work (as shown at end of video) but I read the same with the real crank pulley sockets like the Bluepoint CBSM19 or Lisle 77080 they don’t always work…so sometimes the bolt must be so tight you just need a bigger impact wrench or heat.
But I bet these heavy sockets would help 99 percent of the time unless you have a really weak impact then nothing will help. The lisle is probably made the best because it is one diameter all the way to the front. You could make a heavy socket for ANY size nut or bolt.
LDE Bolt Tension Test – A325 Galvanized Bolts / A194/A563 2-H/DH All Metal Lock Nut