Size----Neck-------------------Chest-------------------Back-------------------Weight

XS------20cm/7.8inches------30cm/11.8inches----- 19cm/7.5inches--------
S-------24cm/9.4inches------35cm/13.7inches----- 24cm/9.4inches-------- 3.3-5.5lb

M------28cm/11inches------40cm/15.7inches----- 29cm/11.4inches------ 5.5-8.8lb

L-------32cm/12.6inches------45cm/17.7inches----- 34cm/13.3inches------ 8.8-13.2lb

Please CHECK dimensions carefully before you decide which size to buy.

Size up if your pet's body length is longer than normal.