I think it's the same as the 510 Mega (as other Vendors call it)
The sell a Mega 510 battery (280mah) to go with the Mega Atty.
The Atty is just a longer version of the standard 510 and takes a longer Cart.
I've been using these for a while - the cart holds more juice, batt lasts about 1.5 as long and has a tiny bit more of a kick -So it's better than a stardard 510 but not a huge amount.
It's pretty good with the Induglence for 3.7v
vaping - but I rarely do that unless I really need to (i.e flat batts) - Since going HV.