These wool applicators slip over a MasterWax Roto Cork to fleece in MasterWax cold apply waxes. A different applicator is required for each cold-apply wax in your waxbox. Mixing waxes on wools can cause negative performance from different ingredients for different conditions. The Drill Applicators are different size (115mm), than the Engine Applicators (125mm). They fit very snug on the MasterWax Roto Corks and are designed around those corks so they do not fit properly over other Roto Corks. Unlike the Engine Applicators, both ends of the Drill Wool Sleeves are white. We recommend marking the side that you use for wax loading to differentiate the side you use for buffing/polishing.