Sandal dhoop is highly concentrated Sandalwood incense.
This is the scent that most people associate with India. It is very fragrant, floral, and lingers in the area for a long time.
Dhoops are a moist, compact incense, without a core bamboo stick. Dhoops tend to be very concentrated scents, and emit a lot of smoke when burned. Thus, you generally only need to pinch a small amount from the roll, shape it, and place it in your burner.