... , B101, B116, B131, B14613. Chinese Standard Metric Core Bits for Single Tube Core Barrels: φ36, φ46, φ56 ... φ160, φ170, φ219, φ27514. Chinese Standard Metric Core Bits for Double Tube Core Barrels: φ56, φ59, φ75, φ ... 9115. Chinese Standard Metric Core Bits for Wireline Core Barrels: φ59, φ75, φ91We can ... all kinds of i diamond core drill bits and reaming shells according to customer's special ...