good quality, casting materail:A3 Steel size: 1" 1"(D)1-1/2"(D) 2" 2"(D)2-1/2"(D) 3"3"(D)4"5"6"8"10"12"available ,D stands for deep throat typefinish: chrome plated, zinc plated,copper plated or black lacquer Market leading products, ductile cast iron replaced the malleable material, its strength, load capacity, anti-bending degree, nuts durability are all superior to malleable, applied more ...