Also checkout Dollar Tree. They have this same adapter kit. You get two sets of AA/AA to C/D adapters for $1.00.
These are adapters OK if you are using them in low current devices, but they do not provide any lasting power compared to standard C/D cell Alkalines. Another problem is that they are made out of plastic with metal contacts. If you use them for prolonged periods in high curent devices, the metal contact will get very hot and melt the plastic adapter. I have already melted two sets in flashlights. One was from Dollar tree and the other from the Big Lots Panasonic deal. If you really have a serious need for NIMH C/D cells, you should get actually C/D NiMHs instead of these adapters.