FenderWedge will pre-seperate the teeth while you prepare the tooth. When the prep is done, remove FendwerWedge and slide your matrix band into place. Firm Stainless Steel shield protects the adjacent tooth from inadvertant contact with the bur. Intro Kit includes 80 Wedges: 20 Purple Refills (Extra Small) 20 Orange Refills (Small) 20 Green Refills (Medium) 20 Yellow Refills (Large)