Voyager found four rings and evidence of ring arcs or incomplete rings. The “Main Ring” orbits Neptune at about 23,812.5 mi (38,100 km) above the cloud tops. The “Inner Ring” is about 17,750 mi (28,400 km) from Neptune's cloud tops. An “Inside Diffuse Ring”—a complete ring—is located about 10,687.5 mi (17,100 km) from the planet's cloud tops. Some scientists suspect that this ring may extend all the way down to Neptune's cloud tops. An area called “the Plateau” is a broad, diffuse sheet of fine material just outside the so-called Inner Ring. The fine material is approximately the size of smoke particles. All other rings contain a greater proportion of larger material.