BS 9220 N003 71st Edition, March 15, 1971
Detail Specification for Flat Rectangular (8.33:1) Rigid Waveguide Tubing - Standard Wall Thickness - General Application Category
Includes all amendments and changes through Reaffirmation Notice , October 1, 2012
Published By:British Standards Institution (BSI)
Covers sizes F22 to F84 in several materials.