Gunmetal bush, brass bush, and LTB bush are all types of bushings used in various applications. Gunmetal bush is made from a type of bronze alloy that contains tin, zinc, and copper. It is known for its high strength and corrosion resistance. Brass bush, on the other hand, is made from brass, which is an alloy of copper and zinc. It is also corrosion-resistant and has good electrical conductivity. LTB bush, also known as Leaded Tin Bronze bush, is made from an alloy of copper, tin, and lead. It has excellent wear resistance and is often used in high-load applications. Overall, the main difference between these three types of bushings lies in their composition and specific properties, making them suitable for different purposes.