Tapered Black Universal Silencer. Pretty cool on a custom bike, but also seen on many Choppers, Scrambler and/or street tracker bikes as well.

They come with a mounting bracket + clamp.

Price per piece

Length: 16" / 406mm
Inlet 1-1/2" and 1-3/4" / 38mm or 44.4mm
Fits either side.
Ideal for choppers and custom applications. 
dB-killer size: 45mm (not included)