LIBO Smart Home 7" Waterproof Video Intercom Wired Video Door Phone Intercom Digital HD Monitor IR Night Vision Camera for House Door Entry System

Being only a four wire system it is quite complicated to set up (particularly the lock activation). However it is worth the money as it is one of the cheapest around & does work as described witha good enough image for its use. I've actually bought a second unit for another room after using the original (without fault) for about a year. The second unit has arrived vith a screen in worse condition than the one I've been using so must be second hand or a demo. Extremely disappointed but at least it works & therefore it is not worth the effort of sending it back.Be warned!