Specs for an AC Power Bank as an Outlet Replacement
You need to know the wattage rating of the appliance, and the wattage rating of the power bank.  These should be marked on the device itself, or at least on the box.

BUT...

Motorized appliances draw a large current surge when they are starting up.  In some cases, up to 10 times the normal power for a fraction of a second.  So the surge rating of the power bank really needs to be at least 10 times the stated wattage of whatever you are plugging in.  Otherwise, you will overload the power bank, and it will shut down.

This may make it impractical to run a leaf blower, grinder or whatever off a small portable power bank.