6-inch on center must be manufactured by Duro-Last. F. Edge Detail: Fascia bar and cover, prefabricated Drip Edge, prefabricated Gravel Stop and 2- Piece Compression Metal Edge must be manufactured by Duro-Last. G. Vinyl Coated Metal: 24 gauge, hot-dipped galvanized, grade 90 metal with a minimum of 17 mil of manufacturers