Let me start by saying these Fhybat replacement batteries are a STEAL for the price. I've been using them with my Dewalt DC9091 drill for about 3 months now, and they've outperformed my expectations.

The 3600mAh capacity means I can work through multiple projects without constant recharging. Last weekend, I built a deck and only needed to swap batteries once during the entire project - that's impressive for aftermarket batteries!

What surprised me most was how well they hold charge when not in use. Unlike some cheaper alternatives, these don't drain quickly when sitting on the shelf. I left one unused for two weeks and it still had about 80% charge when I needed it.

The fit is perfect - they slide into all my Dewalt tools just like OEM batteries. No wiggling or connection issues that I've experienced with other off-brand options.

Now, they're not quite as robust as genuine Dewalt batteries in extreme cold (I noticed slightly reduced performance working in my unheated garage during winter), but for normal conditions? Absolutely flawless performance.

For DIYers or occasional users who don't want to pay OEM prices, these are hands-down the best budget alternative I've found. Two batteries means you'll always have a backup ready, and at this price point, it's almost irresponsible NOT to buy them!