... every pcs slate is inspected strictly to ensure high quality. Grey slate flat roof, 100% natural slate roofing. Natural slate ... physical beauty and its inherent worth to the global community. Grey slate flat roofColor: Rusty, black, green, yellow etc.Standard ... size(mm): 200*400, 200x200, 300x300, 400x250, 500x250, and 600x300 etc.Usual shapes: ...