Airline friendly

I have the the 2nd Gen ASTRO E7 model A1210 26800 mha. Will the airline let me have this as a carry on?

Yes.

Don’t look at the 26800mah, look at the Wh you see its a little under 100Wh.

FAA and CAA both have a convention of 100Wh max carry-on Lithium batteries

https://www.caa.co.uk/Passengers/Before-you-fly/Baggage/Items-that-are-allowed-in-baggage/

Also important, the label showing its within 100Wh

must be legible

. If its worn off then you risk them playing safe and not letting you bring it.

I own the successor Powercore 26800

If label is worn then consider downloading specs and print and keep to attempt to convince the security agent. I cannot find online the Wh or the manual so if you have the one in the shipping box then take that original/copy.