Anodised alloy body in black or silver and pipework and end caps are SS304 stainless and TIG welded. Total weight is about 3kgs. Average power gain is about 4% and requires no rejetting etc. Designed to be within legal dB rating for noise. Can be model specific or made with custom inlet diameter. Comes with all springs, clamps etc too. $400 for a single or $775 for twin systems. I can supply these for Aprilia, BMW, Buell, Ducati, Honda, Hyosung, Kawasaki, Suzuki, Yamaha and Triumph models. Just ask about any particular model and I will let you know what is available.