That's one of the benefits of NIMH(Nickel Metal Hydride). This cell type is usually MUCH smaller and lighter than an equivalent NICD battery.

Downside? Well, it takes longer to charge and these cells DO NOT handle overcharges very well like NICD does. Also, if you have a cell in flight NIMH defaults to an open circuit. But, myself and others have been using them for years in helis, cars, boats, and planes and they are excellent for our hobby.

I just checked Heli-Hut. They no longer list them on their site. But, I think Radical RC and other online battery sellers can hook you up.