I guess a 16 inch chest could wear it, but IMHO, only if the dog is very trained, and you all know ANY baby can B untrained if even for a minute. It seems to me that if the velcro isn't together enough, that it won't be secure enough. That's just me as I have a puller and Mojo doesn't want to come back when called. The one time he slipped a collar that he came to me in, I had to lay flat of my back on the grass to get him to me as he was just too excited to come when I called. The sight of a human being submissive gives them the strong urge to come over and dominate you, and you can grab em right quick,lol. If a dog is well behaved, then maybe the medium would fit a 16 inch chest, but I wouldn't take the chance. I'm thinking since I do love this one so much, of buying one without the lining to see how it fits. I've also thought of buying the large and trying to find a way to put loose wide rubber into the neck/front chest area so it would be smaller or I could possibly draw it up with a drawstring to make the neck more secure, because the medium neck area is fine on him and loose enough. I would be afraid the large neck would B wayyyy too big where the chest might fit better. Wish I could tell yall more, but this is the first one Ive ever bought, so don't know about the unlined ones and how they fit. I would say if your furbutt's chest size is right at the start or in the middle of a size, example: medium says 14-16 inch chest. If your baby is a 14 or 15, it will fit fine. If they r a 16 inch chest, I might try a larger size. I will post back after a week or so of him wearing and let U know if it has stretched any, etc.
