The GRID Foam Roller, the original hollow core roller, features a patented multi density foam surface that delivers firm compression like a sports massage while channelling blood and oxygen needed to repair muscles. The GRID Foam Roller is the ‘go-to’ roller to release muscle pain and tightness, improve mobility, increase circulation, and is recommended by sports doctors, chiropractors, and physical therapists. The GRID foam roller is designed with proprietary Distrodensity zones. This three dimensional surface has a variety of widths to replicate the feeling of a massage therapists hands. Three-dimensional surface allows tissue to aerate while you roll, promoting the flow of blood and oxygenthe nutrients needed to repair muscles. Hard, hollow core hand-wrapped in EVA foam makes it firmer than traditional foam rollers. Environmental design uses less foam than traditional foam rollers. Compact and travel-friendly. Backed by a one-year warranty. Weight tested to support up to 500 lbs/225 kg static load 33cm high x 14cm diameter.