What age do you introduce the e-collar?

[kojakusa]

I don't think it's a question of the dog's age (though I probably wouldn't use it any earlier than six months myself), but at what point in the training process you introduce the collar. As Fowl Play said, intro after you have gone through the basics of obedience (here/sit/heel) and the dog fully understands those commands is a good point to introduce the collar.