The IndiPRO Tools 2.1mm DC to NP-FW50 Dummy Battery Cable allows you to connect to power sources with a 2.1mm DC output, such as the SWIT S-8845 battery. The cable is unregulated and therefore shouldn't be used with sources that deliver more than 7.2 to 8.1V. It measures 20" long and features an NP-FW50 dummy battery for compatibility with the Sony a7 series of cameras.