Size S(90#): Before being inflated, the outer diameter of the swimming ring is 83 cm.the inner diameter is 24 cm. After inflating, the outer diameter of the swimming ring is 75 cm.the inner diameter is 31 cm. Suitable for people of 42.5-65 kg.

Size M(100#): Before being inflated, the outer diameter of the swimming ring is 93 cm.the inner diameter is 26 cm. After inflating, the outer diameter of the swimming ring is 80 cm.the inner diameter is 33cm. Suitable for people of 60-70 kg.

Size L(120#): Before being inflated, the outer diameter of the swimming ring is 115 cm.the inner diameter is 33 cm. After inflating, the outer diameter of the swimming ring is 102 cm.the inner diameter is 41 cm. Suitable for people of 80-110 kg.