AKG C 420 User Instructions page 19

When connected to equipment with a CE sign, this
product conforms to EN 50 082-1.
4.3 Frequency Response
Clean metal surfaces with (industrial grade)
methylated spirits or alcohol.
Clean the foam windscreen in mild soap suds. You
can use the windscreen again as soon as it has
dried.
4 Specifications
4.2 Declaration
of Conformity
4.4 Polar
Diagram
5 Cleaning
19