With WALLDOG, picture hanging is made easy with your ability to install into drywall, plaster, wood studs, metal studs, brick and concrete. The WALLDOG is a one piece screw anchor with aggressive threads allowing for a stronger hold than traditional screws. These screw anchors are removable, reusable and no pre-drilling is required in drywall and plaster. Each kit includes 40 chrome PHP (pan head Phillips) Walldogs , 10 drill toggles with screws, (1) 3/16" masonry drill bit, and (1) #2 Phillips bit.