The item in the image is a concrete vibratory screed or power screed. It is used to level and smooth freshly poured concrete surfaces.
This equipment combines vibration with a screeding action to remove air bubbles and excess water, ensuring a dense, uniform, and flat concrete slab finish.
It is often made of aluminum alloy, which makes it durable, portable, and easy to use.
The machine in the image appears to be a gasoline-powered model, which provides high leveling efficiency and saves on manual labor.