This L-size cool neck ring uses PCM material and freezes naturally below 28°C, maintaining a perceived temperature of -8°C. - Brand: Heart Mark - Product Name: Cool Neck Ring - Color: Blue - Size: L size - Quantity: 1 piece Note: There are four in the photo, but it's one. - Weight: 135g - Material: PCM (Phase Change Material) - Operating Temperature: Freezes naturally below 28°C - Perceived Temperature: -8°C Great deal if you buy now! The product has been inspected from the outer box in a bag. It will be sent in the inner bag, not the box. #HeatstrokePrevention #Cool Thank you for viewing.