Please measure your pet's SIZE and WEIGHT before payment,Your baby usually wears "size S",but it doesn't mean all "size S" will fit him/her.This clothes RUNS SMALL A LITTLE, choose a little bigger size or take each measurement a bit loosely will be more comfortale for your pet.If any of the measurements are between two sizes, choose the larger size.Size:S--9.4" Neck Girth；13.0" Chest Girth；9.0" Back Length；Recommend Weight--3.0 to 5.5 lbsM--11.0" Neck Girth；14.5" Chest Girth；10.6" Back Length;Recommend Weight--5.0 to 8.5 lbsL--12.6" Neck Girth；16.1" Chest Girth；12.2" Back Length；Recommend Weight--9.0 to 12.0 lbsXL--14.2" Neck Girth；18.1" Chest Girth；13.7" Back Length；Recommend Weight--12.0 to 18.0 lbshow to measure pet's size:1.Measure length of Pet's back form the base of the neck to the base of the tail (Length).2.Measure neck circumference if necessary.3.Measure the broadest part of the chest (Girth) all the way around (usually just behind the front legs).Application:Dress it up as a cute dinosaur at a party, great idea for any festival like Thanksgiving Day, Easter Day, Halloween, Christmas, Birthdays, Weddings, Parades, Photo Shoot ,Weekend Parties or Daliy Wear. Get your pet involved in the joy you have at the festival.