The dumbbell stiff-legged deadlift targets the hamstrings, glutes, low and upper back, as well as the core. The purpose of the stiff-legged, as opposed to Romanian deadlift with slightly bent knees, is to engage the hamstrings and low back to an even greater degree.
Strengthening the glutes and hamstrings will carry over to other forms of the deadlift such as conventional
Higher reps with lower weight will lend to hypertrophy of the hamstrings and posterior chain
Also works the calves, quads, and forearms indirectly