First off, they left very little clumping with wet grass...I was very impressed. They fo even better dry. They mulch the grass down quite a bit...much better than the stock Craftsman blades on my riding mower. They are quite a bit heavier than stock so it could be an issue on low horsepower machines but it does say commercial grade, so it is to be expected. There are no installation instructions but if you look at the blades lift characteristics, it makes sense. In my case, it was label towards mowing deck (blank side down to ground). I would buy again.