This listing is for fifty nuts. These fasteners are recommended for use in steel or aluminum sheets HRB (Rockwell B" scale) 80 or less and HB (Hardness Brinell) 150 or less. Thread Size 0.190-24 (#10-24) Thread Code 024 Shank Code 2 Refer to Pic Four for Following: A(Shank) Max. 0.054" Min. Sheet Thickness 0.056" Hole Size in Sheet .003" -.000" 0.250" C Max. 0.249" Min. Dist. Hole C/L to Edge 0.28" For Use in Sheet Hardness HRB 80/HB 150 or less Thread Specification Internal, ASME B1.1, 2B Fastener Material Heat Treated Carbon Steel Standard Finish Zinc Plated