M size: inner diameter 10cm, thickness approximately 2cm, inner circumference approximately 34cm. Neck size guide: 30-37cm 28℃ Cool Ring Cool Band Neck Cooler Ice Neck Ring Running Instant Cooling Cooling Ring Neck Ring Cooling Cool Refreshing Heatstroke Prevention Cooling Goods Neck Hanging Cooling (White, M size) ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ◎ Immediate purchase OK! #YuruttoProducts ← You can see other products ✨ Even if it's new and unused, it has been opened once for inspection of scratches and dirt, and for photography. Please be sure to check the condition in the photos! ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ ┅ 15-28 ✨✨✨✨