Line made of resistant material. The buckle also offers a secure closure, protects against water, dirt, dust, sand, etc. Easy to use and carry, just put the travel gear, roll up the top 3 to 5 times, connect the buckle to complete the seal. This duffel bag is perfect for all outdoor activities: beach, boating, kayaking, rafting, fishing, camping, hiking, snorkeling, cycling, skiing, surfing, sailing etc.