The specific corresponding dimensions are as follows:
An4: inner diameter = 5.56mm, outer diameter = 11.18mm;
An6: inner diameter = 8.7mm, outer diameter = 13.97mm;
An8: inner diameter = 11.11mm, outer diameter = 16.26mm;
An10: inner diameter = 14.2mm, outer diameter = 20.32mm;
An12: inner diameter = 17.46mm, outer diameter = 23.50mm;
An16: inner diameter = 22.23mm
Note: because the inner tube is NBR rubber tube and elastic, it is normal for the measured data to have a certain tolerance( Even metal products used in space rockets have tolerances, please understand).
See column I.D in the following table for details (the unit of column I.D. is inch, and if it is converted to metric system, it needs * 25.4mm, which is the metric data above)