Racing Roto Horsehair Cross Country 70mm brush is part our series of XC brushes in 70mm for combining the brushes that best suit your purpose. Use the horsehair brush is the second step when polishing of the base after applying liquids and hot waxes. First you use a steel brush, then the horsehair brush before you finish off with the nylon brush. Attach two pcs of the 70mm brushes on the 140mm roto cover handle, eg T15-140. Then attach the Roto Cover with the brushes on to your drill. Since you're attaching a 70mm brush on a 140mm roto cover handle you can easily combine brushes on the roto cover handle. One nylon brush and one horsehair brush. We recommend using a drill with a minimum rotation speed of 1800 rpm for best results. Move the brush in overlapping movements from the tip all the way down to the ski's tail