The swivel-tube barrel can effectively increase core recovery ratio, suitable for drilling in formations in which oblique hole comes easy. It is effective to assure hole quality. TypeBitO.D/I.DReaming ShellO.D/I.DOuter TubeO.D/I.DInner TubeO.D/I.DRodO.D/I.DP56 Φ56/Φ39Φ56.5/Φ46Φ55/Φ48Φ45/Φ41Φ50P56 Φ59/Φ41.5Φ59.5/Φ49Φ58/Φ51Φ47.5/Φ43Φ50P75 Φ75/Φ54.5Φ75.5/Φ64Φ73/Φ65.5Φ62/Φ56.5Φ50P91 Φ91/Φ68Φ91.5/Φ79Φ89/Φ81Φ77/Φ70Φ50PA-110 Φ112/Φ79Φ112.5/Φ96Φ108/Φ99.5Φ89/Φ81Φ50/Φ60PA-130 Φ132/Φ97.5Φ132.5/Φ116Φ127/Φ118Φ108/Φ99.5Φ50/Φ60P150 Φ150/Φ116Φ150.5/Φ132Φ146/Φ136Φ127/Φ118Φ50/Φ60P157 Φ158/Φ122Φ158.5/Φ139Φ154/Φ139Φ133/Φ125Φ60/Φ73PA-200 Φ202/Φ167Φ202.5/Φ183Φ194/Φ181Φ177/Φ169Φ60/Φ73P219 Φ225/Φ171Φ225.5/Φ202Φ219/Φ199Φ190/Φ176Φ60/Φ73