Shorty / Short Tube. 16 gauge (1.5mm). For 82-92 Camaro/Firebird F-body with 305/350 SBC V8. Shorty design for power gain from idle to mid-range RPM. Fully mandrel bent tubes made of 16-gauge 304 Stainless Steel. Head flanges laser-cut from 5/16-inch thick steel plates. Flanges flattened by hydraulic press for precise and leak-free seal. All joints TIG welded for resistance against cracking and wearing. Note: The items you received are shown in the figure. If you have any questions later, please contact the after-sales staff in time.