Adopting great quality material, which lets you use it for a very long time. Though it is simple , it' so practical when you use it. The excellent workmanship of our product will bring you a good experience. Easy and convenient to install and use, it is a very useful door viewer. Features - Material: Zinc alloy. - Size: About 2. 75X2. 16X2. 16in 7. 00X5. 50X5. 50cm. -: 2 x AAA batteries ( Not included ). - You can identify who is before you open it. - A must safety complement for home, office, hotel and anywhere you need to view who is outside your door before opening. - It has a simple design, but very practical in use, giving you a . - It is easy to use and install, bringing of convenience to you. - Made of material, which is durable and lasting for use. - Instructions for use: 1. Open to the left or right. 2. Gently press the position of the with your fingers, separate the inner core and out the inner core, and then press 2 AAA batteries into the inner core. 3. Put the inner core back to its original position, and then press it in hand to make it jam. Note: This inner core is a cycle . Click to release, then to jam. - Color: Silver. Package list: 2 x Door Viewer