How to backup video files whilst travelling
 

I wish to backup HD and 4k video files (and possibly Nikon NEF files) while travelling.

This would involve taking TWO HDD copies such that the SD cards can be re-used.

I wish this to achieve this without the aid of a laptop (I will have an iPhone and iPad)

I have read of the WD My Passport Pro and the Nexto Nd2901 and have some questions......

Do any of you know

-If the Nexto 2901 will take 4K XAVC (FS5 and AX100) and Phantom 4 4K?

-Will the WD My Passport Pro allow a second copy to be made to an external HDD (without a laptop in between)

Any other useful comments?

Regards

Martin