Who doesn't love the appeal of Shirley Temple. This little classic has long lasting appeal for the well dressed dog.
Click image to enlarge and see detail

For sizing, you should go by the size your pet is accustomed to and check the specific chart referenced above, but you may find the following a helpful guide for a quick assessment ( inches refer roughly to length measurements):

X-Small: 7" (2.5-5 lb) Small: 9" (5-8 lb) Medium: 10" (8-12 lb) Large: 12" (13-20 lb) X-Lrg: 13" (20-31 lb)