FULLY THREADED TYPE; GRADE 2 STEEL MATERIAL; ZINC PLATED FINISH; 3-1/2 INCH; 13/64 INCH HEAD HEIGHT; 1/2 INCH HEAD WIDTH ACROSS FLAT; 5/16 INCH NOMINAL DIAMETER; UNC-2A THREAD SERIES; 18 TPI; COLOR SILVER; PACKAGING QUANTITY 50 PER BOX