For the pet dog helmet: its strap length is 6.5 - 7.5 inch/ 16.5 - 19 cm, diameter is approx. 3.5 inch/ 8.8 cm, height is approx. 2.2 inch/ 5.5 cm, the circumference is approx. 12.3 inch/ 31.2 cm; For the dog goggles: the applicable head circumference is 20 - 32 cm/ 8.6 - 12.6 inch, applicable low jaw circumference is 17 - 24 cm/ 6.7 - 9.4 inch.