Exmark TTX650EKCE Used Turf Tracer X-Series Walk-Behind Mower Kohler ECV650. Exmark wide-area walk-behind mowers are an investment in the long run. From the fixed-deck, gear-drive Metro to the industry-leading Turf Tracer X-Series, Exmark walk-behinds are engineered for speed, efficiency, durability and a quality of cut that are second to none.