End panels, which contain slits, are designed to fold in both directions and to lay flat to make it easy for you to quickly refer to the strategy you wish to use.
The wave guide contains slits with size of about 1/4 wavelength, in a distance of 1/2 wavelength.
The u-bend wraps around the up stem and contains either holes or slits.
The Inline contains slits and is usually found in the first chamber of the water pipe.