Optimized for backpacks, this 22x28cm size is perfect (compatible with everything from school backpacks to outdoor backpacks). The 3D shape fits snugly against your back for a cool, close contact. It's a super lightweight design at 6mm thick and 190g ✨ From preventing back sweat during commutes to preventing heatstroke for elementary school students, it works as a cooling pad when worn with a backpack, and transforms into a cool cushion or cooling pillow when removed. It blocks out the heat on your child's back during their commute to school, preventing heatstroke with natural cooling that eliminates the risk of frostbite. - Size: 22.5cm x 28.5cm - Material: PCM material - Weight: 190g Thank you for viewing.