ARP  100-1110  1001110 Header Bolts With Hex Style Heads, Chrome Moly Steel With Black Oxide Finish, Set Of 16 Premium grade bolt kit to facilitate installation of exhaust headers Rated at 170,000 PSI, which is considerably stronger than Grade 8 hardware Bolts are 3/8" in diameter and have a 1.000 under head length; 16 pieces Manufactured from black oxide finished chrome moly steel Heads are traditional hex style, and premium-quality washers are included