Supercheap Auto have a similar one on special until 13 January. It's rated at 3300 mAh which I guess is at 12 volts.
The anti-gravity battery is rated 12000mAh at 3.3 volts.
It has the 5 volt USB port, but not the 19 volt one for laptops that the X1 boasts.
They limit it to 2500cc engines where the X1 boasts V8 capability.
A year or so ago I paid the $5 to join their "club". You get the $5 back immediately with a 28 day $10 credit and points for your spend which age-out at 28 days. Over Christmas they credited my account with $5 twice, which I cheerfully bought oil and filters with. Then they gave me $13 credit for the difference in what I'd spent, to be used by the end of January. Obviously it's a loyalty device, but I'd usually shop there anyway, and they have some good specials.