Product Name: 4-inch color visual extension Product Model: QK-W38C-4T ■ with host management center alarm call, intercom, monitoring, multi-song chord tone ringtones ■ image brightness, contrast adjustment, visitors call extension, the extension automatically show the images of visitors, after 60 seconds will automatically enter the waiting state. Hands-free duplex call, unlock function ■ optional features: motion detection recording, camera functions, information publishing, security alarm function (gas, infrared, smoke, door and window magnetic, emergency buttons, etc.) ■ Material: PVC + brushed aluminum decorative surfaces ■ transmission mode: single cable screen (Display): 4 "TFT-LCD Backlight: LED display size (Dimension): 96 (H) X76 (V) resolution (Resolution): 320RGB (W) X240 (H) system format (System format): PAL / NTSC video input (Video input): 1Vpp 75Ω voltage input (Voltage input): DC 12 - 18V ± 10% (typical 12V 130mA ± 20 mA) Dimensions (Overall dimension) : 158 × 232 × 305mm installation method (Installation): plane (86 cassettes)