#8 x 31mm(1-1/4'')..Round washer hd Steel screw. Thread Lo-Root - Qty 100
This is an extension of the Pan head, the head has a washer formed under the head to give a larger bearing area to minimise the screw sinking into the surface and give larger adjustment on slotted holes.
The standard finish is "Lube" which has a bronze/Grey colour. The colour of the screw comes from the heat treatment after which a dry wax is applied to prevent corrosion and ease driving.
#2 is the driver bit size for #8 and #10 gauge screws.