Genuine Malossi velocity stack that fits PHM 38-40mm carbs. These clamp-on stacks can be used on lots of Italian bikes in the 1970's. Made of Polished Aluminum with screens to keep large rocks and low flying birds out. Stacks are 25mm long and 80mm wide at the big end.
NOTE: These clamp-on stacks replace the screw on ones that are out of production