The Fitness Mad Trigger Point set is perfect for acupressure massage and trigger point release. It includes massage balls in 3 different hardnesses which have a diameter of 6cm (2.4"). To massage the shoulders and upper back, the ball should be placed between the back and the wall, whereas to massage the neck the ball should be rolled around between the neck and an open palm. For the lower back or glutes start in a sitting position and for the calfs try sitting or lying on the floor and gently roll around the ball.