On my Hp laptop i have an extra travel battery wich is sort of similar. you attach it below the computer and the computer uses that battery first. it does give some extra hour or 2 of battery time. but its too clumsy and the extra battery tends to loose contact with the computer.
That said the one on the picture looks better than the travel battery for my laptop.
That said the one on the picture looks better than the travel battery for my laptop.