Yellow Mountain Imports Melamine Double Convex Stones, 7.5 Millimeters (Size 28) Full set of Go stones; 181 black and 180 white Go stones Size 28 Go stones; 7.5-millimeter (size 28) double convex Go stones; each stone measures 7.5 millimeters tall and 21 millimeters wide (approximately 0.3 x 0.83 of an inch) Go bowls; 2 plastic bowls (gosu) to store Go stones are included in the set Durable; melamine is an exceptionally durable compound commonly used when strength is essential, such as in kitchen counters and industrial applications; these are excellent stones to use for constant, frequent use; like Yunzi stones, they have a satisfying heft and snap to them; great for go clubs, starter sets or as a substitute for when you do not want to use your expensive set of stones 30-day return policy; here, at Yellow Mountain Imports, we want you to be satisfied with your purchase; you are backed by our 30 day no questions asked money back guarantee so you can buy with confidence