Aluminium, despite excellent mechanical properties, seemed to be something "out of date", being replaced by more advanced materials like titanium or even magnesium alloys. Since the middle of the '90s, Arrow started using aluminium to produce silencers and a couple of years ago showed its line of "dark" aluminium silencers, black anodized. Arrow's aluminium silencers range now is being updated again, introducing the carbon endcap (even if this was available for certain few models) and other improvements in the look. This new line is being identified with the suffix "AK" (transparent-anodized silencers) and "AKN" (black-anodized silencers) on the product code. "AK" and "AKN" silencers are available in Street Thunder, Race-Tech and Maxi Race-Tech versions, these are street legal with removable dB-killer and can be fitted to original pipes (as a slip-on) or on Arrow collectors (as a full system), depending on model. Arrow logo is monochromatic and only for BMW range, the logo is laser-etched. Aluminium and Aluminium "Dark" silencers are available for a wide and growing range of bikes, constantly upgraded, and these ensure top performance and a different look at a very reasonable price. Components and hardware to fit the silencer and approval certificates are given in the fitting kit.