The REVO RCBS20-2BNDL4, is a 4-pack of Super High Resolution Color Cameras. Get crisp, clear images with 450 TV Lines durable, metal case housing, requires 0.0 lux (IR ON). These bullet cameras can be used indoors or out. If a camera is placed outside it should be mounted under an eave or overhangwith the included wall bracket. No visible cable. It comes with free lifetime technical support. Nightvision: Built in Infra Red (IR) LEDs allow indoor/outdoor bullet camera to see up to 80’ in total darkness (switches to black/white video automatically to maximize effectiveness in darkness.) Built in Microphone: For audio monitoring capability. Wide Angle 3.6 mm Fixed Lens for larger viewing area.