Availability: Usually ships in 1-2 weeks.
 
V-mount to B-mount Conversion
KA-B21S conversion plate allows you to adapt V-mount batteries to the cameras with B-mount plate, like ARRI ALEXA 35, Blackmagicdesign URSA CINE.
KA-B21S doesn’t change battery voltage. The B-mount side outputs the same voltage as V-mount batteries.
 
28.8V Battery to Power ALEXA35
SWIT Bi-voltage V-mount battery recommended
Use SWIT PB-H290S 14.4V/28.8V Bi-voltage V-mount battery, the KA-B21S plate will active the 28.8V high voltage output mode of PB-H290S, and provide 22- 33.6V voltage to power the B-mount cameras ALEXA 35 and BMD URSA CINE.

* The PB-H290S can output 14.4V for all regular V-mount devices, and is compatible with all regular V-mount chargers.
 
V-mount to Power ALEXA35
26V/28.8V V-mount Batteries Compatible
You can use pure 26V or 28.8V high-voltage V-mount batteries to power ALEXA 35 with the KA-B21S conversion plate. SWIT HB-C420S 28.8V 420Wh huge capacity V-mount battery is a nice solution to provide extremely long duration to the ALEXA 35.