Usage Tips:Finger Strengthening Exerciser Balls Design: This finger ball exerciser has just the right squeeze to strengthen our hand. These hand strengthener grips are very effective for keeping the ball in hand during exercise, didn't bind, and didn't interfere with the alignment of fingers during use. Customized Individual Five Fingers Buttons: Easily adjustable for each finger to increase the force required to press each plunger and the silicon rubber pads are comfortable on the palm and finger tips. Better for Improving Strength & Dexterity: This is such an easy and painless way to strengthen our fingers and hands that even have considerable arthritis. It allows us to painlessly squeeze, unlike some other exercisers we've used. Real Finger Strength Training Changemaker:These hand exercisers are great for guitarists, office workers, pianist, musicians, artist, craftsperson, woodcarver, webpage designer, etc. A must have for building finger Colour:B:Black Material:ABS+Silicone Package Contents: 1 x Finger Exerciser Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.