How is it Measured? Outside Dimension A(inch) X Wall Thickness B(GA and inch)

Item Size & Description are as follows:

3/8" OD x 20 GA (.035" wall)

1/2" OD x 16 GA (.065" wall)

3/4" OD x 16 GA (.065" wall)

1" OD x 16 GA (.065" wall)

1" OD x 14 GA (.083" wall)

1" OD x 11 GA (.120" wall)

1-1/4" OD x 16 GA (.065" wall)

1-1/4" OD x 14 GA (.083" wall)

1-1/4" OD x 11 GA (.120" wall)

1-1/2" OD x 16 GA (.065" wall)

1-1/2" OD x 14 GA (.083" wall)

1-1/2" OD x 11 GA (.120" wall)

1-5/8" OD x 11 GA (.120" wall)

1-3/4" OD x 16 GA (.065" wall)

1-3/4" OD x 11 GA (.120" wall)

2" OD x 16 GA (.065" wall)

2" OD x 14 GA (.083" wall)

2" OD x 11 GA (.120" wall)

2-1/2" OD x 16 GA (.065" wall)

2-1/2" OD x 11 GA (.120" wall)

3" OD x 16 GA (.065" wall)

3" OD x 11 GA (.120" wall)

3-1/2" OD x 16 GA (.065" wall)

3-1/2" OD x 11 GA (.120" wall)

4" OD x 16 GA (.065" wall)

4" OD x 11 GA (.120" wall)

5" OD x 11 GA (.120" wall)

5-1/2" OD x 11 GA (.120" wall)

6" OD x 11 GA (.120" wall)

8" OD x 11 GA (.120" wall)

10" OD x 11 GA (.120" wall)