C&A Pro Boondock Extreme BX Skis - Yellow 77170399 Countless hours of R&D and on-location to perfect a ski for todays lightweight mountain snowmobiles The BX has a progressively curved rocker on the bottom of the ski, on both sides of the keel, to allow riders a smooth transition when navigating through trees The integrated snow traction grooves on either side of the center keel aid the ski in maintaining grip on the snow at even the most severe angles The tail of the BX tapers to a slimmer profile to help initiate a transition into a side-hill for effortless navigation Ski also features a larger than normal kicked up tail to allow riders to use reverse in situations they never have been able to before