... slight press, visible,press again, automatically unlock This system can be used in apartments,villas,hotels,offices,public ... ,you can use the indoor monitor where the wireless signal can reach,indoor montior can hang on ... on the desk,tea table,dining table etc.Outdoor extension Power Supply: Input AC 100-240V 50/60Hz ... 5°F~131°F 2.4 inch Wireless video doorphone doorbell Intercom System 1 V more more V 1