These are custom knurled shoulder machine screws manufactured domestically in the USA in grade 5.1 steel material with zinc and yellow finish. Production was run at a relatively small quantity of 4,000 pieces, which was split into two shipments approximately 4 months apart to our OEM customer. Material certs and dimensional test reports were provided to our customer with the parts, as well as the standard certificate of conformance. Our internal part number is M111957-2.