Size Chart:XXS (Chest10" Back8")， XS (Chest12" Back10")， Small (Chest14" Back12")， Medium (Chest16" Back14")， Large (Chest18" Back16") Product Detail:(1)Perfect for every day wear，sleep time and photos.(2)Your fur baby will be wrapped in comfort with this dog pajamas.(3)Machine washable，four-legged design with elastic waist Note:(1)Choose the size up to the size chart for perfect fit.(2)Your baby usually wears size S doesn't mean all size S will fit him/her.(3)If any of the measurements are 'between' two sizes， choose the larger size.4.Take each measurement a bit loosely.