Robuta

https://saemobilus.sae.org/standards/as9210c-bolt-machine-steel-diffused-nickel-cadmium-plated-double-hexagon-extended-washer-head-uns-k14675-195-ksi-min-3125-24-unjf-3a AS9210C: BOLT, MACHINE - STEEL, DIFFUSED NICKEL-CADMIUM PLATED, DOUBLE HEXAGON EXTENDED WASHER... nickel cadmium