Safe: The putty is made from an unscented, non-toxic material. Not suitable for young children under 3 years of age. Convenient: Each different strength putty is colour coded and comes in their own separate, easy to open containers. Bring these with you anywhere and use it anytime. Variable Strengths: With five different resistance levels to choose from, you can gradually increase the level of exercise intensity depending on progress. Hand Strength Training: Great for strengthening the hand muscles and improving fine motor skills. Can be used in rehabilitation, physical or occupational therapy.