For the beginner to advanced user, the Grid Foam Roller helps work through the tight muscles, knots and kinks that encourages functionality and range of motion. To put simply, the Grid is for anyone who wants to move better. The Grid roller was designed with a three-dimensional surface of varied widths meant to replicate the feeling of a massage therapist's hands. The patterns allow tissue to relax as you roll and promotes the flow of blood and oxygen responsible for carrying nutrients needed to repair muscle. The Grid's hard, hollow core is wrapped in EVA foam making it firmer than traditional foam rollers all while using less foam, making it environmentally conscious. The GRID roller measures 13 inches long and 5.5 inches in diameter and has been weight-tested to support up to 500 pounds of static load making it travel-friendly and extremely durable.