Solid-Core Eva foam; Patented GRID design replicates the feeling of a massage therapist's hands, like three rollers in one; Unique three-dimensional surface helps aerate tissue, promoting the flow of blood, oxygen, and the nutrients needed to repair muscles; Medium-density, solid-foam construction provides comfortably moderate pressure; 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; Solid EVA foam construction is more durable than traditional polyproylene foam rollers; Medium-length size (18 inches or 45 cm) is ideal for targeting most areas of the body; Size: 18-inch x 5.5-inch x 5.5-inch; Warranty: 1 Year