Aut pop door - where to buy?

[Gwen]

Where can I buy an auto pop door? I've done a search and only come up with instructions on how to make one. I'd prefer to purchase, not at all a DIY'er. I'm in the U.S. Google searches online bring me places in other countries, but not the U.S.

Also, do you need to have electricity in the coop?

Thanks!