The Dooly has two 7/16" Flat-top runners mounted on a plate for each ski. The four contact lines on the snow surface will help decrease darting of your sled as it makes its own groove in the trail. When in a turn, only one of the Dooly bars will be in contact with the snow or ice. Therefore, a Dooly with 6" of carbide on both runners will have the same turning power as a single runner with 6" of turning carbide. The Dooly is available in 4", 6", and 8" of 60 degree turning carbide for Arctic Cat, Polaris, Ski Doo and Yamaha snowmobiles. Each Dooly is packaged individually.