public sealed class ExtensionHeader : Header, 
	ISIPCloneable<ExtensionHeader>

Public NotInheritable Class ExtensionHeader
	Inherits Header
	Implements ISIPCloneable(Of ExtensionHeader)

public ref class ExtensionHeader sealed : public Header, 
	ISIPCloneable<ExtensionHeader^>

[<SealedAttribute>]
type ExtensionHeader =  
    class
        inherit Header
        interface ISIPCloneable<ExtensionHeader>
    end