Our Merged Collectors are constructed with the primary tubes joining as they transition into the collector to form a spear eliminating sharp edges and voids to reduce turbulence. This allows more precise management of the sound pressure waves (tuning) and improves aerodynamic flow. These 3 into 1 and 4 into 1 collectors are made from the lightest materials possible; a pair of 17/8" x 31/2" weigh only 5 lbs. 4 ozs. Sold in pairs only.