The foam rollers, each model with a different density but all with the same standard design the GRID - which reflects the feeling of the masseur's hand. Self-massage, Foam Roller. The Grid, the massage roller is designed for all types of people, from long-distance runners to Yoga enthusiasts. If you need a deep massage with myofascial release at the level of the spine or a certain muscle group The Grid is the product of choice. It is only 33cm long and 12.70cm in diameter. It supports up to 270kg.