The 5 cells are AAA size from Sanyo. It's the NiMH type of 700 MhA. The pack comes pre-assembled and shrink-wrapped.

Presenting this pre-assembled 6V battery pack, which has been designed especially for use with the Impulse PRO. Comprising of lightweight aluminium mounting posts, a carbon plate and 5 Sanyo 1.2V AAA 700Mha batteries. This is the neatest and most lightweight battery pack available as well as helping in lowering the cars centre of gravity.It fits the Impulse PRO perfectly, but can also be used on the other Impulse cars when the Carbon Radio plate Conversion kit has been installed (#801110).
Always use an appropriate NIMH Battery charger for this set!