Developed by a dental hygienist, Hagishiri-kun (Grinding Teeth Protector). Simply place it on your lower molars to protect your precious teeth from teeth grinding and clenching. Sleep care, teeth grinding対策 (countermeasures), mouth guard. Comes with a storage case. For both men and women. Free size. Special two-layer structure. Patent pending. Use when sleeping, at bedtime. Use at night.