Great lumber, these can be used for studs, shelving, fence backer rails or any project where you need strength but with a little less strength, cost and size compared to a 2 x 4. I have also used these to create walls between tubs and showers for plumbing to save some space and money. I used these extensively in my shed for the walls and shelving.
As with any lumber, you need to pick through the pile for good pieces. These are kiln-dried with <20% moisture but will still dry out a little further. Before they dry out further they take nails and screws well, after you may need to pre-drill holes.
They are not sanded and are of general rough lumber quality. They can be stained or painted if need be. The type of wood (different from store to store) is either spruce, pine or fur. These are not pressure treated and should not make contact with the ground or they will rot.