Pirahna&tm. Paper Scoring Tool Has Four Hardened Stainless Steel Blades That Penetrate Through he Old Wallpaper But Not The Drywall, Scoring The Old Wallpaper Is Essential For The Adhesive Remover To Penetrate Through The Paper To The Old Paste, The Oval Soft Grip Shape Is Easy To Manage Even When Wet, When Used In Conjunction With Pirahna Removers Your Job Is Shorter & Easier.