Kidney Belt 2.5 FlexMesh. Light, breathable lumbar support. The 2.5 FlexMesh kidney belt is designed to be light, cool, and supportive. Ultra-lightweight, protective and breathable FlexMesh material construction makes this comfortable enough for all-day wear, while offering the lower-back support riders need on rough terrain. Main Features: Lightweight, breathable FlexMesh material construction. Comfortable enough for all-day wear. Supports the lower back.