This item uses a special welding process to join the fabrics. Two pieces of fabric (parts) are layered together in a special machine, pressurized, and irradiated with electromagnetic waves, creating a durable, seamless bond. The special welding process causes a chemical reaction between the two fabrics at the molecular level, preventing re-peeling or separation. The main material is CORDURA 500 denier ripstop fabric, which is both waterproof and strong, so you can use it with confidence.