Size:(Just be sure to measure your dogs in order to best fit your dog).

S: Chest: 58-64 cm/22.83-25.2" Waist:34-51 cm/13.39-20.08" Nect:36-41cm/14.17-16.14" Suit for 7.5-18 kg / 16.53-39.68 lb dog.
M: Chest: 70-81 cm/27.56-31.89" Waist:41-55 cm/16.14-21.65" Nect:51-60cm/20.08-23.62" Suit for 18-28 kg / 39.68-61.73 lb dog.
L: Chest: 80-87 cm/31.5-34.25" Waist:66-99 cm/25.98-38.98" Nect:61-78cm/24.02-30.71" Suit for 28-40 kg / 61.73-88.18 lb dog.

Tips: Can fit medium to large size dog such as Alaskan, Samoyed, Shepherd, Tibetan mastiff, etc. Please check the size.
Features:

Specifically drawstring design on both sides of the backpack,can play a role in the contraction of the outer bag when full and decorative.
Adjustable straps & breathable mesh harness for maximum comfort & fit and could let your dog feel good.
Perfect for walking,shopping,hiking and jogging with your dog.
Package included:

1 x dog backpack.