Screedmatic with 3.5 hp Briggs and Stratton engine uses an up-down-forward motion which goes with the operator and brings the fines and fats to the surface making finishing time shorter and eliminating honey-combing. The contractor is able to use large-sized aggregate for slabs, increasing the compressive strength of the concrete. Handles spans to 20 feett of high slump concrete and spans to 16 feet of low slump concrete. Use two-by-fours to 10 feet, two-by-sixes to 16 feet and two-by-eights to 20 feet. Note: This item cannot be returned to Amazon.com. If for any reason you need to return this item, please contact our customer service department at home-returns@amazon.com.