regina kette 525zrt gb 110rs rh 137zrt 011Z ring chains feature the patented z44 sealing rings, which greatly improve performance and wear life, Making Previous X ring and z ring chains obsolete, 50% reduction in friction compared to traditional o ring, constant lubrication from special hgt lubrication fried Provides Long Life, High Carbon Alloy Pins to Minimize Wear and Increased Roller Thickness to Polong Durability, Thicker Outer Plates and Quad Riveting For Greater Tensile Strke, Riven