Individually adjustable across back and neck by Velcro closures. Sizes are belly circumference in centimeters. Color: Yellow Size 40: Neck circumference: approx. 30 to 40 cm / chest circumference: approx. 40 to 50 cm Size 45: Neck circumference: approx. 40 to 50 cm / chest circumference: approx. 45 to 60 cm Size 55: Neck circumference: approx. 50 to 70 cm / chest circumference: approx. 55 to 85 cm Size 70: Neck circumference: approx. 55 to 70 cm / chest circumference: approx. 70 to 100 cm