But even if these adaptors are good quality-wise, at $5.99 each for these adaptors, the economics are not very good compared to Tenergy D cells. After paying $5.99 for these adaptors, you have to buy the batteries on top of it. Assuming $12 full price for four Eneloops/Duraloops, you're putting another nine dollars worth of batteries in each adaptor. That's $15 to replace ONE Tenergy D cell. And at $18.49, TWO Tenergy D cells don't cost alot more. Unless you are getting these adaptors because you want the option of running on AA batteries in emergency situations (in addition to running D cells), I just can't see how paying more money to get less capacity by running AA batteries in these adaptors is a better idea than getting real D cells like Tenergy. Even if you already have lots of AA batteries, the cost of these adaptors ($12 for two) is starting to get a little close to the cost of two Tenergy D cells ($18.49 for two).