Body Part: Neck and shoulder, arm, upper back and chest, middle back, hips and glutes, upper leg, and lower leg; Condition: Achilles tendonitis, DOMS (Delayed Onset Soreness), forearm / bicep tendonitis, IT band syndrome, runner's knee, neck pain, piriformis syndrome, sciatica, and shin splints; Foam: 30% bio fibers, 30% ethylene vinyl acetate, 20% recycled polyethylene, 20% polyolefin elastomers; Core: 100% recycled acrylonitrile butadiene styrene; Patented GRID design replicates the feeling of a massage therapist's hands, like three rollers in one; Crafted from up to 30% bio-based materials; Hollow core design is strong enough to support up to 300 pounds; Unique three-dimensional surface helps aerate tissue, promoting the flow of blood, oxygen, and the nutrients needed to repair muscles; Durable hollow core design won't break down with repeated use like traditional foam rollers, providing consistent performance over time; EVA foam is water- and sweat-resistant, making it easy to clean; Smooth foam composition rolls comfortably against skin and clothing; Ideal for both those new to foam rolling and advanced users; Size: 13-inch x 5.5-inch x 5.5-inch