I will have to check my notes, but it's the first calipers that Tundra owners were getting replaced. I followed a write up on TTORA and I had to dremel out the brake line a bit. I know, it sounds scary, but its held with no issues for several years. The brakes work great. I bet if I had to go back to the stockers, I would be shocked at the difference. Since adding the brakes, I added more weight, so stopping would be interesting with the original calipers.