This is a 14g 75mm galvanised batten screw. 5mm hex drive, 10 threads per inch, self countersinking with 4 ribs, type 17 with 2/3rds thread. Batten screws are a more presentable alternative to nuts and bolts. As they are countersunk they finish flush leaving no ugly or potentially dangerous obstructions. Useful in playgrounds, for decking, in treated pine or any outdoor structures. Class 3 finish to AS3566 for external use in mild, moderate industrial or marine environments. Use a driver bit such as
these.