Gosh most people on here will tell you about not using a collar on a small dog especially a Yorkie but I would not even use a prong collar on a large dog as it causes neck problems down the road. I had fabulous success with the Halti (bottom link to Petsmart has xxs) to get one of my boys to learn to walk on the lead.
http://www.doglogic.com/halter.htm http://www.allourpets.com/htmls/halticollar.shtml http://www.geocities.com/jetflair/halti.html http://www.petsmart.com/product/inde...gkw=halti&sr=1