Small:

• around the neck of the dog (green color on the picture): 17.5-25.5 inch (44-64 cm)
• around the chest behind the front legs (red color on the picture): 24.5-30 inch (62-77 cm)
• chest strap (blue color on the picture): 23.5 inch (60 cm)

Medium:

• around the neck of the dog (green color on the picture): 26-34 inch (66-86 cm)
• around the chest behind the front legs (red color on the picture): 30-35.5 inch (77-90 cm)
• chest strap (blue color on the picture): 26 inch (67 cm)

Large:

• around the neck of the dog (green color on the picture): 28-35 inch (71-89 cm)
• around the chest behind the front legs (red color on the picture): 31.5-40 inch (80-102 cm)
• chest strap (blue color on the picture): 28 3/4 inch (73 cm)

Extra Large:

• around the neck of the dog (green color on the picture): 28-35 inch (68-90 cm)
• around the chest behind the front legs (red color on the picture): 39-51 inch (99-130 cm)
• chest strap (blue color on the picture): 30 inch (77 cm)