These Grade-8 socket head studs are recommended for small tube headers where there is adequate clearance around the header flange bolt holes. The integral socket head eliminates the need of double nutting for easier installation. Self-locking hex flange nuts spread the clamping force evenly for a great gasket seal. Studs are black plated and the nuts are bright zinc plated. 3/8''-16 x 1.5'' (12 studs & nuts)