... 131, T6S-14612. B Series(ISO3552-1) Metric Core Bits: B36, B46, B56, B65, B76, B86, ... 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 ... all kinds of i diamond core drill bits and reaming shells according to customer's special requirement ...