The battery on offer is one of the strongest and most powerful batteries we can find in the 9V battery size. - The minimum capacity of 500 mAh has been achieved through the use of dedicated Li-ion cells.
The new Li-ion batteries in the 9V battery size at a nominal voltage of 7.4V achieve twice the rated capacity expressed in mAh of their Ni-MH counterparts. Ni-MH batteries, on the other hand, have a marginally higher average operating voltage (nominal) - usually 8.4V.