Nishikawa Keeps Oshiri no Makura (Buttocks Pillow) Stabilizes bone position and naturally maintains ideal posture. Size (approx.): Width 44 x Length 41 x Height 18 cm Brand: Keeps Composition: Surface/Sides: 100% Polyester (Antibacterial treatment) Back: 65% Polyester, 35% Polyurethane (Non-slip treatment) Core: Urethane foam Color: Gray