The smoke detector spy camera system includes a smoke detector with HD camera inside, a TV displayer, transmitters and an earphone. It is very best for small casino games and private room games. The scanning camera lens is about 2-3 meters far away from back marked cards and the scanning range is 1.5 meters. When you use this product to cheat at poker games, you have better worked with your friends. The background is from the gambling scene 50-100 meters or 200-300 meters away. Moreover, this is one to one camera lens and other camera lens can not scan these back marked cards. You can choose battery or AC power. It is the perfect camera system for playing Texas hold and Omaha game!