Science Museum Strength Ball £6.66
# 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 gyro.
# How many revs can you build by spinning your wrists? The record stands at over 14,000 RPM.
# As the revs build so does the torque, making it a real challenge to control.
# Batteries required: 2 x LR41.
# Suitable for ages 10 years and over.