What's the difference between ordinary cat's eye and electronic cat's eye?

Benefits of electronic cat's eye 1: Your child can use the cat's eye. Benefit 2: Your old man can easily see who is outside the door. Benefit 3: Don't worry about someone peeking outside. Benefit 4: Easy installation, only three 7th batteries are used. When someone rings the doorbell outside, it will ring like a telephone. When you hold down the button, the image will be real. It's different from building intercom! Don't worry about wasting electricity. Three batteries can last for half a year or even a year. Benefit 5: beautiful, when looking more comfortable, ordinary cat's eyes will not have this benefit! Electronic Visible Cat's Eye Beijing Sales Company: Beijing Century Wanda Trading Co., Ltd. Address: 48-5- 10 1 Tel: 010-52453009/319-59499.