A battery pack with a housing, at least one battery cell contained within the housing, a first terminal and a second terminal. The housing includes a substantially ovoidal surface which is substantially symmetric about a first axis of symmetry and a second axis of symmetry which is transverse to the first axis. The surface has first and second substantially linear terminal openings. The first opening extends substantially parallel to and is non-coincident with the first axis, while the second opening extends substantially parallel to the second axis. The first and second terminals are disposed within the housing adjacent to the surface. The first terminal is accessible through first opening and the second terminal is accessible through the second opening. A device for using the battery pack is also provided.