Designed to be the most effective foam roller on the market, every detail on the R4™ Body Roller was considered. The size, surface texture, material density and shape were optimized to target specific muscle groups. The key focus points are the center groove to align with the spine and neck, along with a profile to help loosen tight IT-bands, calf muscles and many other areas of the body. Feedback from elite athletes and physical therapists were crucial to the development of the R4™ Body Roller.
 
https://rollrecovery.com/products/r4