Review on 🔋 Kastar 2-Pack 1.2V Ni-MH AAA 1000mAh Rechargeable Battery with Tabs | Ideal for Electric Razors, Toothbrushes, High Power Static Applications, Telecoms UPS, Smart Grid, Electric Mopeds, and Waterpiks by Amy Perry

I used these to change the batteries in my Norelco BG2040 using ifixit.com's manual. These batteries actually fit with a margin of a few mm. I used the pre-soldered tabs as a spring to maintain tension to hold the batteries in place as I bend them in a zigzag pattern. I can't get the charger to 100% charge these batteries yet, but I believe it's probably just a matter of draining them and then fully charging them. And the battery capacity is a few hundred mAh more, so the charger and circuitry might just not be designed to continue charging past the 750mAh that the original batteries had. In general they worked and I didn't have to solder. If you want to replace the BG2040's battery, it will work fine as long as you follow all the instructions in the ifixit guide.