Not too sure what it was. Probably a long #10 into a 4x4. Was playing around with it when I got it.
Although yesterday I tried it with a 3/8 lag into a lead concrete sleeve. That was a no go. Power cut out right away. Wasn't expecting to be up to the task. The first gen fuel didn't skip a beat. I'm just not a fan of how it just cuts off power instead of limiting current. In more realistic usage where it would work just slowly it'll cut out.
I do love how it works with smaller fasteners and doesn't trash bits. Just thrown off by the torque limit. If it were just underpowered that would be one thing but this will just stop doing the job. If I didn't know and didn't have my impact driver with me I would be pissed.
It is great for the vast majority of what I do. Just has one large downfall.