Neck, ears, face, but not the forehead (stings the eyes when it runs down with sweat). Needs to be sweat proof, SPF30 or greater (greater cannot be advertised in Australia), and cover both UVA and UVB rays. I use the same sunblock on my arms and occasionally my legs. I was caught out this weekend in 19C weather because I forgot to put sunblock on my arms. Another thing, because the vents on my helmet are huge and, unfortunately, I am getting thinner on top, I also wear a skull cap to protect the noggin.