BOSCH GBA18V80-2PK 18V CORE18V® Lithium-Ion 8 Ah High Power Battery, 2-Pack

Bought a few of these. 8ah is the sweet spot, IMO. Not too big or heavy but plenty of power and use. I would imagine 12ah would be too cumbersome to carry around but has a better run time than 4ah, obviously. Great for more constant use tools like angle grinder, sanders, saws, etc. Still using a standard charger so takes 2-3 hours to charge a dead one.

I usually only keep 4 AH on hand but my vacuum and reciprocating saw run them out quick. These are a must have for high demand tools. Got them on sale for a really good price. Little hefty in a drill or impact however.

I didn't even realize what my tools were capable of doing until I started using these batteries. They're excellent for the oscillating tool. The upgrade was definitely worth the money. The batteries last a long time and have a lot more power

Bosch is top tier! All Bosch products are first class! The 18volt Bosch system is super powerful! I have too many Bosch tools to count! I bought these for the vacuum cleaner to add to the run time! Love Bosch tools!

Great battery set