If you're a DIY manifold builder this collector is a must have! This is our investment cast turbo merge collector for a divided T4 turbo. Made from 304 stainless steel, designed to work with 1.5" schedule 10 or 40 nominal pipe. This collector will save you hours of labor, no more wasting material trying to figure out angles on the band saw. Reduce welding and porting time drastically. Flange is threaded for M10x1.25.