Hollow core foam roller with unique recessed channel delivers direct compression while avoiding sensitive areas or targeting specific muscles Roller evenly compresses muscles to re-hydrate tissues and improve mobility; ideal for post-workout recovery sessions Features patented hollow core design, this sweat resistant foam roller delvers targeted total-body massage Includes access to free online instructional video library on foam rolling education from the experts at TriggerPoint This 13 in foam roller is 5.9 in in diameter with a 500-pound weight limit; this roller is made of easy to clean 62% EVA and 38% ABS