These are great, we use the 20v router in our shop for round overs and trim cuts. The standard 3amp hour batteries don't last, but these are great. They ballancy weight wise on the router, and their lasting power is amazing. Kept an eye on the listing and purchased them when they went on sale. Great value for the price, must have for any level of serious work.

I purchased a pack of two , and didn’t use them for a month or so . The time too replace them had came and went before I’d even opened the package . I opened them up excited too try them out ,and one was defective. I thought I’d made a huge mistake by not testing them before return date passed . I contacted company and they immediately sent me a new one . Would definitely buy from this company again . Their customer service was very impressive .

Bought these in 2017 and they have been tested in the most rugged environments . From rain & mud, even snow, to months on end in dry lake bed very dusty places like Burning Man(Black rock desert/ mojave desert (118 temps))! They have fallen off 12 and 16ft ladders many times while attached to drills. I've used them to tap lumber into place when I couldn't reach a hammer. They are still about as good as new as far as how they run the tools I have. And I have about 80% of dewalts line of cordless tools. The 5 amp hr battery will last many days at a time without recharging using them on a drill/impact driver for 8 hours strait driving 3 inch deck screws into framing wood. I've gone thru 2 sets of impact drivers and many drills and these same batteries are still working like the day I bought them. The days of being up on a ladder in a precarious position and your tool going dead mid way into driving a lag screw into a heavy beam are OVER! BUY THESE BATTERIES NOW if your on the fence! Excellent deal here!

Drilled 40 holes in one day on the same battery and it never slowed down
It was only 6 inches thick though
A big plus, the cold temp in no way affects the performance of Lithium Ion batteries
Perfect for icefishing

Love this Dewalt system. Just ordered the jigsaw. Next up will be the trim nailer. These 5 and 6ah batteries last a long time. I'll never run out of power, and with the 4 bank charger I'll never have to wait for a battery again.

These are great batteries. Much better than the batteries that came with my hammer drill and last all day on one battery. I have not used them long but seam to be quality at a reasonable price. The price on Amazon was much better than Lowe’s and Home Depot.

I recently got the Dewalt M2 drill/driver set and the 20v circular saw, the drill set came with 2 of these 4ah battery packs and they're great so I bought this pair so I had a spare plus one pack for each tool.

These 4ah batteries are great - I get really good life out of them using them in the drill, impact driver and circular saw. I've just built a pretty huge 9' x 8' shelving and workbench unit in my garage - from a full charge, I was able to build the whole thing without recharging. Amazing compared to my old 18v powered stuff. Charge time is also faster which is a bonus.

The 4ah battery packs from my research offer the best $/ah ratio and these seem to go on sale more often than other sizes so it's worth keeping an eye on the price and grabbing some when the price is right. In case yu're confused by all the different Dewalt 20v battery packs like I was, here's a handy guide illustrating the various models. These 204's are the best bang for the buck!

Model - Capacity - Color - Size
DCB 200 - 3.0 Ah - 20 Volt standard black - thick
DCB 201 - 1.5 Ah - 20 Volt compact black - thin
DCB 203 - 2.0 Ah - 20 Volt XR premium yellow - thin
DCB 204 - 4.0 Ah - 20 Volt XR premium yellow - thick
DCB 205 - 5.0 Ah - 20 Volt XR premium yellow - thick

The thin ones are the same size and approximate weight - the thick ones are the same size and approximate weight.

So for example at today's current pricing, the 205 5ah XR's ($189) are almost 50% more expensive than these 204's ($131), for only 25% more runtime (1ah per battery). The 2ah XR batteries are half the capacity of these 204's and almost identical price ($129). Therefore in terms of capacity vs $$ these 4.0ah 204's are the best value.

The 'fuel' indicators on these batteries are a super useful addition - very handy to be able to see easily how much juice you have left. Really glad I went for these 4ah packs, I was kind of tempted to go for smaller capacity but happy I stuck with these. They add a bit of weight/bulk to your tool (especially noticeable on the drills and the otherwise lightweight 887 impact driver), but this is a minor downside compared to the power and life you get out of them.

If you've got Dewalt 20v tools and you need good battery life, grab a pack of these, they're great!

PS - to answer the 1 star reviews who bought fakes - always make sure with this kind of item that it says 'ships from and sold by amazon.ca' up top near the price - that's the safest way! If it ships from some unknown seller, avoid it!

Hope that helps.

SO MUCH BETTER THAN 2.0MAH batteries! The run time on these is amazing. Especially with a brushless tool. I dont know how people could stand using NiCd tools. Lithium last forever especially the bigger batteries like this! Even my circular saw lasts FOREVER using these. Felt like i was constantly changing them on 2.0mah batteries.