Metlok Cyclonic 680® is a concealed fixed roof and wall system suitable for use in cyclonic wind regions. Fully tested and approved Metlok Cyclonic 680® allows for thermal expansion and contraction of sheets making it ideal for long run applications. Manufactured from 0.42mm and 0.48mm BMT COLORBOND® and ZINCALUME® steels, Metlok Cyclonic 680® is suitable for use in commercial and industrial applications for roof pitches as low as 1 degree (1 in 50).