I got one similar from Maplin a few years ago. Battery was smaller than my motorbike battery - something like 8Ah. Might be ok for starting a lwan mower, But it didn't last a month in my garage - battery destroyed first time it was used in anger trying to get next doors car started.

There is a correlation between Ah and CCA but only taking internal battery construction into account as well - it's to do with the plate area (bigger area > more CCA) and electrolyte volume (more volume > more Ah).

Conventional car batteries have relatively big plate areas and relatively low electrolyte volume - that's compared to, say, traction batteries - but in practice car/motorbike batteries are used for many thing with different labels stuck on.

Many leisure batteries, for which Ah is important but not CCA, are just car batteries with handles and a new label - I'd expect jump starter packs to be just motorbike batteries - the demand for specialist batteries of 8 Ah but 600+ CCA is very low so I doubt they're built in that configuration.