Ergonomically designed to fit small to large hand sizes.perfect for men,women,seniors and teens. Design for athletes and sports enthusiasts who want to increase their hand,wrist,forearem and finger strength for rock climbing,shooting,bodybuilding,golf,tennis etc. The easily adjustable dial and wide range of tensions make the hand exerciser a popular choice for those with arthritis,rheumatoid arthritis,tendonitis,carpal tunnel,tennis elbow and those recovering from a Broken wrist and tendon surgery. Great hand strengthener for musicians including drummers as well as guitar,piano and violin players. Color: black and blue Material: ABS Size about: 10.5 x 15cm Package Contents: 4 x Hand Dynamometer Grip 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.