small:
Backpack after the film length of 24 cm， the former length of 19.5 cm，
Bust adjustment range: 32 cm -42 cm;
Strap width of 3 cm， strap adjustment length 68-108 cm.
Rubber band and dog buckle adjustment length: 14 cm -20 cm.
Medium: backpack after the length of 27 cm， the former length of 21.5 cm，
Bust adjustment range: 37 cm -48 cm;
Strap width of 3 cm， strap adjustment length 68-108 cm.
Rubber band and dog buckle adjustment length: 14 cm -20 cm.
  Large: backpack after the film length of 31 cm， the former length of 22.5 cm，
Bust adjustment range: 47 cm -57 cm;
Strap width of 3 cm， strap adjustment length 68-108 cm.
Rubber band and dog buckle adjustment length: 14 cm -20 cm