From my experience, the Mag drop-ins won't work in alot of your standard PR flanged holders. True, the nite-ize and craftsman aren't the best, but they're more readily available, especially for those that like to physically see what they're buying before they commit. I use them in about 5 of my beater lights. Since you're putting it in a 2D rayovac, the cheaper one's should do fine. The better drop-ins might get damaged cause of the excess heat generated.