The DVR16-3425 is equipped with a 1TB HDD inside the box for recording your footage. With a H.264 recording technology, Smartphone integration using a widget on a Windows, Blackberry or iOS, HDMI output, and a usb connector to transfer video recordings to a portable format. Record onto the built-in hard drive for up to 30 days, and longer with motion detection. You can add an external hard drive to the eSATA port. Suitable for 16:9 monitors. A big perc of this system is to connect to the internet and your smartphone in minutes using your app, whether using an iOS, Windows, or Blackberry device. Connect from anywhere you are and log into your cameras using your 3G/4G enabled internet connection. You can have the system record +15 days using lower settings. The default settings give a maximum of 3 days recording.