Science Museum Strength Ball £6.59 (save £4.40) @ WHSmith
Free delivery to store
Strengthen your arm muscles with this nifty little device. Pull the red cord to get the gyroscope inside the ball rolling then by holding the strength ball and spinning it with your wrist the revs will build up and improve your arm strength. The most enjoyable way to exercise and strengthen your hand-grip and forearm. Switch on the LCD Revometer, and using the pull cord provided, spin the internal gyroscope. The test is to see how many revs you can build by spinning your wrist - 5,000 or 10,000? As the revs build so does the torque, making it a real challenge to control.