5/16-Inch Grade 43 Chain, 20 Feet. Also known as High Test chain, this is a higher strength carbon steel chain that provides a higher strength to weight ratio than Grade 30 as well as increased resistance to wear. Used for load securement, binding, construction, logging, and agriculture.From the Manufacturer5/16-Inch Grade 43 Chain, 20 Feet. Also known as High Test chain, this is a higher strength carbon steel chain that provides a higher strength to weight ratio than Grade 30 as well as increased resistance to wear. Used for load securement, binding, construction, logging, and agriculture.