PQ PQ3 Impregnated diamond core drilling Bit Impregnated diamond core drilling Bit PQ3 series 8 , 14mm 16mm for Rock hardness of F1-F14 Impregnated diamond core drilling Bit PQ , PQ3 series 8 , 14mm , 16mm for Rock hardness of F1-F14 Detailed Product Description Features: High Penetration Rate, High Speed,High Performance Product Name: Core Drill Bits Crown Height: 9mm, 12mm, And 16mm Type: Turbo Type Diamond Core Bit Certificate: ISO9001 Use: Hard Rock Impregnated diamond