Malleable Iron Shell Block Double Sheave With Swivel Hook-China LG™,also known as Malleable Swivel Hook Pulley.
Pulley and Block are common lifting mechanisms use for rigging and can be suitable for Manila Rope, not for Wire Rope.
The main material we use carbon steel and surface is Hot Dip Galvanized, so it could be anti-corrosive and we usually use in Ocean Operation.