The  36-inch ring diameter trowels are powered by a 5.5- and 8-hp gasoline-powered engine, respectively. Both models finish seven square feet of concrete per revolution. The 46-inch ring diameter SCT46H80 and SCT46H110 are designed for larger applications and are driven by 8- and 11-hp engines, respectively. They can finish 11.5 square feet of concrete per revolution. Stow Construction Equipment, a div of Multiquip. 877-289-7869. www.stowmfg.com