Robust and Low-Noise: High-quality solid cast iron core dumbbell encased in durable rubber, ensuring lasting strength and protecting your floors. Various Size Range: Fitvids rubber encased hex dumbbell available in multiple sizes (5 LBS, 10 LBS, 15 LBS, 20 LBS, 50 LBS) - PAIR; (25 LBS, 30 LBS, 35 LBS, 40 LBS, 45 LBS) SINGLE.