hand grip exerciser are made of high quality material,which is environmental protection. No peculiar smell ,will do no harm to the skin.They are all durable and not easily damaged. .The hand grip is perfect for improving strength, power and speed in the wrists, fingers, and forearms. An undoubtedly best choice for Climbers, Guitar Players, Athlete and Musicians to enhance the flexibility of fingers and wrists. It’s also helps recover from hand injury,arthritis,carpal tunnel and tendonitis. 3.15" L x 3.35" W x 0.78" H