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: Yellow - Size: L size - Quantity: 1 piece Note: There are four in the photo, but it's one. - Weight: 135g - Material: PCM (Phase Change Material) - Freezing Temperature: Freezes naturally below 28°C - Perceived Temperature: -8°C Great deal if you buy now! The product has been checked in its bag from the outer box for confirmation. It will be sent in the inner bag, not the box. #HeatstrokePrevention #Cool Thank you for viewing.