Two Stainless Steel Flathead Screws, 4mm Hex Head. This Stainless Steel Flathead Screws (2) set from Sunwayfoto includes two stainless steel screws each with a 4mm hex head of the type used for many Sunwayfoto products such as the DDP64MX panoramic Indexing Rotator and the DDP64SX panoramic Indexing Rotator.