This secret lamp camera can read the back marked cards well. You can see the marks on TV or your cell phone instead of wearing contact lenses. Also, the back marked cards marks can not be seen by contact lenses or sunglasses. The sender of the camera, you can choose wireless, WiFi, or 3G/4G. So you can choose one kind of sender for you. And the short distance is 100m. But if you use Wifi, 3G or 4G, the signal can be sent to any countries. The camera lens is hidden into the lamp, so our lamp camera for back marked cards is very secret. No one can find the camera lens and if you use phone camera to scan our lamp, you can not find it. It is very fit for gamblers.