This heavy duty workout sandbag is a training gear. Both the inner and outer bags are made from nylon 1050D Cordura. It is durable, waterproof, and sand-proof with high-quality materials and advanced sealing techniques, ideal for all-around training and practical fitness shaping. | Vevor | | Workout Sandbag, Heavy Duty Workout Power Bags with Handles, 100 lbs/45 kg Slam Bag | Black | Best Buy