Features: Advanced Temperature Control Technology: This backpack cooling pad utilizes PCM (Phase Change substance) technology to provide long lasting cooling without moisture accumulation. It maintains a comfortable temperature difference of around 7°C from body heat. consistent & Reusable Build: The cooling pad naturally solidifies when placed in cool surroundings or refrigeration below 28 degrees and can be used over 100,000 times. Made with quality TPU, it's water resistant, skin friendly, and designed for repeated cooling use. Ergonomic & Portable Design: Measuring 30.5 × 24.5 cm and weighing only 300g, this compact cooling pad fits most backpacks such as school bags. Versatile Cooling Uses: Ideal for daily commutes, school, travel, and outdoor activities. Functions well as a seat refrigerator for cars, strollers, or chairs, providing adjustable temperature management for various needs. Certified Safe & Mild: Tested by Japan's Cultural Goods Safety Laboratory, this gentle cooling pad is safe for all ages and pets. Specifications: Technology: PCM phase change substance (freezes naturally below 28°C) substance: good-density leak-proof TPU Size: 30.5 × 24.5 Cm Weight: 300g (-) existence: more than 100,000 times recycling characteristics: physical constant temperature, denial condensation, denial wet clothes Certification: passed the tests of the Japan Stationery Safety Testing Institute Applicable: backpacks, strollers, car seats, pet mats Package Includes: 1 x PCM backpack cooling pad note: Pay attention to the storage methods.