Blue Flame, oval, twin spout, stainless - legal, but with removable baffles and plugs to increase noise as desired; solid quality, light weight, great prices, easy fit, no re-jetting.
I've had one on my Aprillia RSV FOR 10 years, we've had one on the Gen 1 Fazer 1000 for about 7 years and also had one on th Fazer 600 for 3 years.
All performed flawlessly and still looking good (no rust, no degradation and still a good sound).
We'd totally recommend them.