You can learn about lock bypassing by having it explained to you or by reading about it. You can learn a lot more when you can actually see it happen right in front of you. That is why the visible cutaway practice locks that ITS Tactical offers are so valuable. They let you see how your tools interact with the various components of the lock.
They recently added a Visible Cutaway Practice Handcuff to their line of available visible cutaway locks. So, whether you want to practice shimming or picking, you can see exactly what is going on inside the handcuff as you manipulate it.
Check out the Visible Cutaway Practice Handcuff at ITS Tactical.