Hangzhou Singer Building Material Co.,Ltd, located in Hangzhou, China, is one of the leading manufacturers producing asphalt shingles, metal shingles, pvc gutter system and aluminum gutter system. Our San-gobuild (or SGB) branded products have the ISO9001 and SGS certifications and are exported to many countries in Africa, Asia, Europe and America. They are becoming more and more popular both in China and overseas. For more information of our products include prices, you can contact me.