The Atomos Connect SDI to HDMI Converter is a convenient way to convert an SD, HD, or 3G-SDI signal - depending on the transfer rate of your SDI device - to an HDMI signal for the purpose of running the SDI signal on an HDMI device (such as in, for example, connecting an SDI-equipped camera to the Converter by SDI and outputting the signal to a top-resolution large screen local HDMI display).
Aside from the handy form factor, what's additionally very much convenient is that the Converter is battery-powered. It features an internal battery that provides 2 hours of power and accepts separately-sold NP series batteries that can last up to 32 hours, so depending on the battery size; you can power the Converter continually into the next day if you want. And if you have a second battery as well, then you can replace one for the other and the internal battery will kick in during the swap and thus you can keep the converter working day after day without pause. (You can also employ AC power if you have an NP-style device that functions as an AC adapter.)
As another point of convenience, multiple Converters are stackable one atop another and can even be housed in a 1RU rack. HDMI to SDI Converters are alternatively also available and can be stacked together with SDI to HDMI ones as if they were the same. When stacked, multiple units can be powered by the same battery, by the one on the uppermost Converter in the stack. The Converter has one SDI input and likewise one HDMI output.