Santa’s Lil Helper" Embroidered Dog Pajamas. This is the BEST PJ on the market today. It features Super Soft 100% Thermal Cotton. These pajamas have a fantastic stretch which makes it very comfortable to wear and easy to put on. We embroidered the bottom with “Santa’s Lil Helper.” It also features an OPEN TAIL END for quick potty breaks. Important Sizing Note: The following measurements are the dimensions of the actual product, not of the pet they fit. After measuring your pet, make sure all measurements fit within the following dimensions (with a little room to spare in the chest and neck). X-SMALL Back Length: 8" Chest: 10-13" (Most Important) Neck: 7-10" SMALL Back Length: 10" Chest: 13-16" (Most Important) Neck: 10-12" MEDIUM Back Length: 12" Chest: 16-19" (Most Important) Neck: 12-14" LARGE Back Length: 15" Chest: 19-22" (Most Important) Neck: 14-17