Tool set made of high quality steel with great match of hardness and toughness, thus prolongs its service lifePacking including: 1pcs 2" boring head, 1pcs R8 shank, 9pcs 1/2" carbide boring bar,3pcs allen wrench2" Boring head with R8 shankHead size: 2"Boring bar hole: 1/2"When the direction of the dial is reversed, the backlash between the gear train is listed below.Overall length --- Bore depth --- Min. bore2-1/4" -------- 3/4" --------- 5/16"2-5/8" -------- 1-1/8" ------ 5/16"3" -------------- 1-1/2" ------- 5/16"2-5/8" ------- 1-1/8" ------- 7/16"3-3/16" ----- 1-11/16" --- 7/16"3-3/4" ------- 2-1/4" ------- 7/16"3" ------------- 1-1/2" ------- 9/16"3-3/4" ------- 2-1/4" ------- 9/16"4-1/2" ------- 3" -------------- 9/16"