Just picked up these for testing. As per the photo they're Energizer Accu Recharge Pro NiMH.
Now remember when you buy rechargeables, they're not all created equal. They range in capacity from around 1300mAh up to 2900mAh so decide whether you want quicker charging or longer lasting. There are also NiCD still out there which you don't want as they're small capacity and develop a memory quite quickly.
I plumped for the 2000mAh which take about 4 hrs to fully charge from flat on the supplied charger. They're charging now so when ready, I'll time my play and confirm how many hours of Touching I get out of them.