Special Features: 1. 4" TFT Screen or B/W CRT 2. Talk + Monitor + Unlock 3. Waterproof and prevent dust design 4. Metal face plate 5. For villa system 6. Call indoor monitor Specification: 1. Power course: DC 16V 2. Screen: 4" Flat CRT or Color TFT LCD panel 3. Effective resolution: 420 lines or pixels / 480H*234V 4. Ring way: Dingdong ring or chord are optional 5. Match way: One to one, one to two. 6. External dimension: Monitor: 230L*165W*30H(mm) Camera: 240L*120W*60H(mm)