Designated Metric Size  | 
        Gauge Size  | 
        Range of Outside Diameters  | 
        Inside Diameter Tubing  | 
      |||
Normal- Walled  | 
        Thin-Walled  | 
        Extra-Thin- Walled  | 
      ||||
Min.  | 
        Max.  | 
        Min.  | 
        Min.  | 
        Min.  | 
      ||
0.20  | 
        33  | 
        0.203  | 
        0.216  | 
        0.089  | 
        0.105  | 
        ---  | 
      
0.23  | 
        32  | 
        0.229  | 
        0.241  | 
        0.089  | 
        0.105  | 
        ---  | 
      
0.25  | 
        31  | 
        0.254  | 
        0.267  | 
        0.114  | 
        0.125  | 
        ---  | 
      
0.30  | 
        30  | 
        0.298  | 
        0.320  | 
        0.133  | 
        0.165  | 
        ---  | 
      
0.33  | 
        29  | 
        0.324  | 
        0.351  | 
        0.133  | 
        0.190  | 
        ---  | 
      
0.36  | 
        28  | 
        0.349  | 
        0.370  | 
        0.133  | 
        0.190  | 
        ---  | 
      
0.40  | 
        27  | 
        0.400  | 
        0.420  | 
        0.184  | 
        0.241  | 
        ---  | 
      
0.45  | 
        26  | 
        0.440  | 
        0.470  | 
        0.232  | 
        0.292  | 
        ---  | 
      
0.50  | 
        25  | 
        0.500  | 
        0.530  | 
        0.232  | 
        0.292  | 
        ---  | 
      
0.55  | 
        24  | 
        0.550  | 
        0.580  | 
        0.280  | 
        0.343  | 
        ---  | 
      
0.60  | 
        23  | 
        0.600  | 
        0.673  | 
        0.317  | 
        0.370  | 
        0.460  | 
      
0.70  | 
        22  | 
        0.698  | 
        0.730  | 
        0.390  | 
        0.440  | 
        0.522  | 
      
0.80  | 
        21  | 
        0.800  | 
        0.830  | 
        0.490  | 
        0.547  | 
        0.610  | 
      
0.90  | 
        20  | 
        0.860  | 
        0.920  | 
        0.560  | 
        0.635  | 
        0.687  | 
      
1.10  | 
        19  | 
        1.030  | 
        1.100  | 
        0.648  | 
        0.750  | 
        0.850  | 
      
1.20  | 
        18  | 
        1.200  | 
        1.300  | 
        0.790  | 
        0.910  | 
        1.041  | 
      
1.40  | 
        17  | 
        1.400  | 
        1.510  | 
        0.950  | 
        1.156  | 
        1.244  | 
      
1.60  | 
        16  | 
        1.600  | 
        1.690  | 
        1.100  | 
        1.283  | 
        1.390  | 
      
1.80  | 
        15  | 
        1.750  | 
        1.900  | 
        1.300  | 
        1.460  | 
        1.560  | 
      
2.10  | 
        14  | 
        1.950  | 
        2.150  | 
        1.500  | 
        1.600  | 
        1.727  | 
      
2.40  | 
        13  | 
        2.300  | 
        2.500  | 
        1.700  | 
        1.956  | 
        ---  | 
      
2.70  | 
        12  | 
        2.650  | 
        2.850  | 
        1.950  | 
        2.235  | 
        ---  | 
      
3.00  | 
        11  | 
        2.950  | 
        3.150  | 
        2.200  | 
        2.464  | 
        ---  | 
      
3.40  | 
        10  | 
        3.330  | 
        3.500  | 
        2.500  | 
        2.819  | 
        ---  |