A laser screed is a machine used to both level and vibrate concrete used in floors. The method is typically used in large floor pours, such as retail or warehouse structures.
A laser-emitting device is placed on a static location outside the pour. Two laser receivers on the ends of the screed align themselves with the laser to keep a floor pour level during placement. An auger inside the screed levels and vibrates the concrete as the screed pulls over the wet surface, similar to any hand-screed operations.
The advantages of the laser screed are (generally) more level and even-thickness concrete floors. The disadvantages are cost and the necessity of a competent operator.