You know those tiny muscle knots you get from doing computer work with a mouse all day? The ones right at the base of the skull that inevitably develop into a tension headache? I built this massage device to really get at those knots.
One hemisphere is knobby, and the other is round to roll smoothly in the palm of your hand. The Acorn also works great on muscle knots along the spine or those elusive buggers under the scapula. Overall diameter of the Acorn is approximately 2" (5cm).