This intake manifold is designed to work with 19mm to 22mm carburetors in 4-stroke machines. It will fit many 50cc to 125cc engines in ATVs, Dirt Bikes, or Scooters. Commonly used in conjunction with PZ19 & PZ22 carbs. Opening is 22mm, the mounting holes are 4.8mm and 4.5mm apart centre to centre respectively.