When picking a new jump starter keep in mind that they use sealed lead acid batteries essentially the same as those in the attached link but probably lower quality than Panasonics.
If you want "capacity" you need size and weight.
The panasonic link will give you some basic info regarding the sizes and capacities. However, they don't include the common CCA number used for automotive batteries. The Pegasus link for a battery similar to my Panasonic shows 180 CCA.
https://www.pegasusautoracing.com/produ ... ?RecID=115http://www.panasonic.com/industrial/bat ... -vrla.aspxThe size for my race car is a nominal 17 to 20 Ah (depending on the supplier).
http://www.panasonic.com/industrial/inc ... 1220AP.pdfI've had good luck with the Panasonic but still replace them every few years (my car does not have an alternator so the battery has to be at its best for both starting and running the engine).
Finally, are you sure about the 490 CCA rating? That is a "car battery" capacity which will require a battery larger than the typical jump starter unless you use a Lithium ferrous such as a Ballistic Battery for a lot more money:
https://www.pegasusautoracing.com/produ ... RecID=9405