Shell: Polyvinyl Chloride Imported CONSISTENT SHAPE AND BALANCE: PVC soft slam balls for exercise offer balanced and stable workouts; Whether slammed, tossed, or grabbed, a threaded slam ball keeps its shape EASY TO GRIP WEIGHT BALL: The textured surface of slam balls for exercise offer a stable hold for overhead smashes, chest passes, and Russian twists; Big slam ball prevents slips or drops HIGH DENSITY SAND-FILLED: Weight balls for exercise with hard shell prevent sand from leaking during intense workouts; Soft sand-filled slam ball for home does not bounce or roll for enhanced balance VARIOUS WEIGHT OPTIONS: Mid size slam ball leg raise is available in options of 10, 15, 20, 25, 30, and 40 lbs; Strength training weighted balls cater to many fitness levels FULL-BODY WORKOUT: High-density slam balls for men are designed for wall slams, squats, or other power movements; Slam balls for exercise baseball support various exercises to enhance overall fitness