Fleece Performance Exhaust Manifold Stud Kit - 7mm External Hex Head Fleece PerformanceAll New! Fleece Performance stainless steel exhaust manifold stud kit for Cummins. Our exhaust manifold studs are produced from aged 603 stainless steel and feature a 7 mm external hex head for easy installation. Impervious to rust and corrosion, these studs not only look good, but allow for higher clamping force and simplified manifold installation. Higher Clamping Force (Torque to 40lbs using anti seize) Includes 12 point nuts and washers Aged 603