Features: Comfortable: Due to the softness of the silicone, hand grip feeling comfortable to touching, extremely flexible, no deformation. Durable and Practical: The silicone material are very stable, and the silicone finger exerciser is durable and practical. Optional Color: There are many color and different resistance levels of finger exercisers for you to choose from.. Perfectly Sized for a Comfortable Fit for: Perfectly sized for grip strength training for both men and womens. Easy to Clean: The finger stretcher expander hand grip trainer can being cleaned after washing with water. Specifications: Material: Silicone Color: Pink/Green/Blue/Gray/Black Outer Diameter: approx.7.5cm/2.95in (More Size Detail, Please See Photo.) Grip Strength: Green: 20-30kg; Pink: 30-40kg; Blue: 40-50kg; Gray: 50-60kg; Black: 70-80kg Package Includes: 1Pc Hand Gripping Rings note: Please allow 1-2cm error due to manual measurement. Please make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thanks!