Refillable Reusable Heat Pack - Microwave Safe, Non-Toxic, Leakproof, Built Tough, Roll Up for Easy Storage. Hook & Loop fastener. Great for self soothing heat, keeping food warm, and more!Designed for easy, HOW TO USE COOLERPAK: Fill with water (DO NOT pour boiling water into Coolerpak), microwave in 2 minute increments until reached desired temperature, use as needed. Caution as water may be very hot! EXTENDED HEATING: CoolerPak meets FDA and Prop 65 standards, and its large capacity helps keep your food warm for extended periods of time. COOLER ATTACHMENT: Attach to your hard or soft cooler with the included velcro strips, form freestanding walls, or attach multiple packs together for larger coolers. SAVE SPACE: When not in use, simply drain and pack CoolerPak away in a compact size, making it easy to store in your cooler or backpack without carrying unnecessary bulk or weight. BUILT TO LAST: Crafted from 600D TPU flexible fabric, CoolerPak is built to withstand rugged outdoor adventures while maintaining its heating capabilities. PATENT: US 12,480,700 B2