The sizing chart(JUST FOR YOUR REFERENCE,THERE MAYBE LITTLE DIFFERENCE FOR THE REAL GOODS) as following,Please MEASURE your pet before buying.

 How to measure
Chest:Measure the thickest part of chest.(ususally behind the two legs)
Neck:The girth pf necklace
Body:Make sure your dog is standing properly,not sitting or laying down.Measure from along the dogs backbone from the neck to 5cm(2 inch) front of base of tail.
-You should select the size of chest at least 1 inch(2.5cm) larger than your dogs B.L.

Size     Body     Chest       Neck

S           9"      14"             9.4"

M      10.6"    16.5"          11"

L        12"      18.8"       12.5"

XL     13.7"    20"          14"