The 18? Foam Massage Roller allows for a simultaneous double arm and legwork. Loosens tight muscles, soothes soreness Improves mobility. The PBLX Foam Roller soothes soreness, improves mobility, and is a proven tool for muscle regeneration, stress relief, and improving alignment, and flexibility. The 18” size allows for a simultaneous double arm and legwork, helping you to develop better balance and stability.