These are the new Radius mowers. From Exmark. Exmark Radius S-Series delivers the cut quality and durability professionals demand at an unbeatable value. Powered by Kohler ZT engines, with Hydro-Gear integrated transmissions and up to 9 mph fwd. ground speed Radius improves productivity, but an operator seat with adjustable isolation technology and elastometric vibration control (EVC) means maximum comfort.