Service Description It is a service to smooth the surface of concrete, especially used in cases of floors of factories, warehouses, workshops and gas stations, and it is often considered a final surface that does not need finishing. To be used after "1-4" hours (initial setting time) after pouring the concrete. In conclusion, using a "helicopter" fan on concrete surfaces offers a range of benefits, from blocking pores to ensuring flatness and smoothness. It's a cost-effective and efficient way to create a high-quality surface that is durable, long-lasting, and free from imperfections.