Die hard has been a household Brand name for so many years because of quality and these batteries are just that. I always use die hard rechargeable batteries in my camera flash, They have never let me down and give me good long life from a very draining product.
2 out of the 4 batteries didn't work. Compare to Duracell and Eneloop rechargeable, they do not hold a good charge. Voltage is lower too. Pay more for Duracell or Eneloop.
I have been using these batteries for a couple weeks and no problems yet, excellent product, well made.
Quality batteries and charger.