Ideal sports tool for tennis, bowling, golf and all your daily strength needs, helps to condition and strengthen your hands, wrist and forearm muscles. Triple steel tension coil build; strong plastic handles are textured and molded. When use, you use single hand or both hands hold the hand grip tightly, and strongly force the two handles to close up, then release. You can repeat the exercise at home or gym, so easy. Note: Please make an effort to grip the handle tightly in case of accidently springing out to hurt people.