Here is a video that explains these receptacles. http://www.childoutletsafety.org/video.html Here in central Ohio Northwest Electric and Plumbing (OH. Lic. #26286) installs these for as little as $10.00 each. Yes there is a minimum charge. Or you can replace these yourself if you have a working knowledge of residential electric. You could as a Realtor offer to have these replace for your client to help make a sale. As you can see it is not pricey. You can reach Northwest Electric and Plumbing at 614-214-1487. (6 comments)