For Higher Commerce Co., Ltd. is a professional building material company located in Qinhuangdao, We could provide you various kinds of slate used in buildings.The specifications of the slate roofing tiles as followings,Size:(mm)500 * 250, 400 * 250, 400 * 200, 300 * 200, 254 * 254, 200 * 200.Thickness: (mm)5-7, 6-8, 7-9.Other size, thickness ans shape are available upon special order. The technical report of our selected roofing material are available. The test was done in the way reqired by BS 680:Part2:1971.If you have this kind of enquiry, please feel free contact us. We could provid you the best price and high quality.Thanks & regards, Benny For Higher Commerce Co., Ltd.