1. Color: Black - Opening and closing indicator 2. Opening/closing signs, privacy sliding door sign indicators (black) are suitable for commercial storefronts, restrooms, office doors, walls, windows, restaurants, retail salons and other places. 3. Clear and eye-catching: The fonts are printed clearly. One side has a red background and the other side has a green background. The difference between the two colors makes it quite conspicuous in its position. 4. Quick switch: This sign is for sliding doors, and one sign can display two states. Just place it horizontally, and the slider can slide easily, smoothly and relatively quickly to show the "open" or "closed" state. 5. Wide range of uses: It is suitable for various shop doors, office doors, meeting rooms, home offices, dormitory rooms, etc., where people hope to avoid being disturbed during indoor work. It is also suitable for outdoor exhibitions, recording studios, public service buildings and other places. By sliding the slider to show "open" or "closed", one can simply and clearly know the state of the room.