I am the husband of this Amazon account owner.I have a Philips Norelco beard trimmer, about ten years old, that wasn't holding a charge anymore. I bought a Remington PG525 to replace it and I was very unimpressed with it (though I never used it). It felt cheap and flimsy. I returned it. I opted instead to try to repair my old one. And I did it with one of these batteries.The diameter of this battery is ever so slightly larger. I did have to cut some of the plastic inside the housing so it would fit. Additionally, I broke some of the tabs on my old trimmer - these are the tabs inside that keep the two halves locked together. It required soldering (and these batteries came with solderable tabs - the solder wetted up them very easily!).I've used it several times with success.NiCad (Ni-Cd, NiCd, Ni-Cad) batteries can typically be one-for-one replaced with NiMH batteries since the battery chemistries produce similar voltages. In this case, the voltages are close enough that I can use the same charger that came with my Philips Norelco beard trimmer, and it seems to run the motor just fine. Actually, it seems to run it better - but that is probably because my point of comparison is an aged battery versus a new battery.Unfortunately, I just have no use at all for the other 3 batteries! I would have paid just as much to buy just one!