PetSafe Dog Collar Batteries (2 Pack)

I have used this particular product since 2007. I bought this product from retail stores up until last fall when I purchased 2 packages through Amazon... As far as the product goes, my first dog used to wear one of these batteries out every 3 - 4 weeks because Charlie was constantly testing his boundaries and swimming with his collar on, which wears them out more quickly... Our current dog, Kali, never, ever tests the boundaries and detests water... Over a couple of years, I measured her battery usage as needing replacement every 3 MONTHS, which is a significant difference from what my other dog used to do... Pure laziness in taking advantage of the ease of buying through Amazon.com, I bought two packages here to try out and to save the 25 mile trip to a store that carries them here out in the boonies of NH. With Prime, they arrived on time last October and everything seemed fine... at first... However, quite suddenly I noticed that Kali's batteries were dying out at somewhere around 5 - 6 weeks instead of lasting the 3 months they'd been lasting with the store bought ones I'd always used prior to these... Not sure why that is, but I suspect one of three reasonable possibilities: 1- Perhaps this seller is selling factory seconds through Amazon that they don't ship to other retailers? Or even very old batteries with limited shelf life? (Disclaimer: this is pure speculation on my part and NOT to be confused as a direct accusation or as having any proof behind it other than my own personal experience and applied logic) 2- Perhaps a new piece of equipment caused it... When I replaced the collar unit that had worn out over continuous use during the period of 2007 to late 2012, somehow that **could have** changed the way the batteries responded to the collar signals and made an enormous difference in how fast the batteries died... The collar had been malfunctioning over a long period of time, unbeknownst to me at the time, and ultimately stopped beeping half the time when it was taken outside of its normal limits... Since I don't know WHEN that began happening, although it couldn't have been throughout Kali's entire lifetime here (she is 3 1/2 now) because, at first, I routinely took the collar off and tested where the boundaries were beeping at because I was trying to keep her out of a specific spot so did a lot of testing... The only possibility of the collar's failure is for an approximately 6 month period where I was no longer testing, but the batteries were still lasting the 'usual 3 months'... So, I don't think it's the replacement collar that has caused the batteries to last much less now because nothing has changed with her, she still knows her boundaries, and unlike Charlie before her, does NOT test them every few minutes... so there's no INCREASED activity wearing out the battery just because the collar now works properly again... (Charlie loved to run free and knew that power outages and dead batteries happen with frequency, so tested relentlessly like the dinosaurs in Jurassic Park... lol).... Plus, even during the time that the old collar was likely failing, the batteries were lasting the same average time as the batteries used with her replacement collar and previously when the original collar was fully functional ... That is UNTIL using the batteries bought from here... So the two differentials here are a new collar and Amazon batteries... But, I believe that I've shown why the new collar is unlikely to be the reason... 3- Or perhaps Kali has suddenly begun secretly testing her boundaries only when I am not looking just since I purchased this batch of batteries from the PetSafe factory's Amazon account... Which would be rather ingenious of her as well as awfully coincidental too... I won't speculate on the possible motives a clever little dog might have, but she's not exhibited any other truly ingenious, sneaky tendencies with anything else, so I believe this can also be ruled out as likely... Of course, anything IS possible and I may have overlooked something... But, I rather doubt it... Thus, my strong belief that there is SOMETHING AMISS with the batteries purchased from Petsafe through Amazon... (how rotten of them to do that to Amazon's reputation, eh?) ... That said, my review of the product, itself, outside of THIS issue and THIS method of purchase from the dealer would rate a full FIVE rating as would the PETSAFE PRODUCTS that they are used in... I love PetSafe's wireless system with its 90' perimeter... It's reliable, convenient, and simple to teach the dog his or her boundaries... Just don't go moving them a lot of you'll get a pup like our Charlie was who relentlessly tests them to see where they can go that day... The batteries have lasted only 3 weeks with that type of dog but, LIS above, up to 3 months with a dog that knows its territory and stays away from the edges of it to avoid the warning sounds or being 'zapped'... Take my warning about buying from this dealer throught their Amazon account for what it is worth... There is, of course, some room for doubt as to the REASON why the batteries from here don't seem to have as much OOOOMPH as the store bought ones and anyone can get a 'dud' package... But why so damned many of them from Amazon customers??