TPI (20 pcs) 1/2"-20 Premium Black Chrome Closed Bulge Acorn Wheel/Lug Nuts , B903542HT/BC-20, 1.4" Tall, 13/16" / 21mm Hex Size Bulge closed acorn design, 1.4" Tall, 13/16" Hex, Cone Seat. Our black coating gives the durability of chrome with the look of satin black paint Greater seating surface to prevent damage during installation. Cold forged and heat-treated for Optimal Hardness. Precision Threads