Engineered for High Speed steel rigid dies fit head types 504A, 711, 713,811A,815A, 816, 817, and 842. With a capacity of 1/2"-3/4" inches, these threading dies are made to provide longevity and reliability. The rigid die grinder set is highly adaptable and resists every type of weather & work environment. With 11-1/2 TPR this pipe threader die set is very ideal for construction sites, factories & plants We guarantee a lifelong service for this rigid die set and compensate for all defects & deficiency.