Quantity: 50pcs self-drilling drywall anchors. Size: 13 x 42mm. Heavy Duty: Zinc alloy self-drilling anchors with screws for drywall or other lightweight panels. It is ideal for drywall and coated walls. Heavy duty metal wall anchors are available for single or double layer drywall. No Pre-Drilling Required No pre-drilling required. You don't need to figure out your drill bit size to drill holes. Just pierce the paper skin and tighten it at home. Use an electric or manual screwdriver. Use only the screws provided. Easy Installation: Insert the fixing point into the drywall until the threads of the self-drilling plug engage the drywall. Maintain pressure on the anchors and screw them into the drywall until the fasteners align with the drywall. Place the screws in place and tighten until you are sure the mounting screws are tight. Multi-purpose: The self-drilling metal wall anchors are designed for use on plaster walls and double-sided drywall. Typical drywall accessories include shelves, bathroom hardware, mounting brackets and hooks, picture frames, cable ducts, plumbing hardware, outlets, electrical equipment and accessories, handrails, shelves, mirrors, wood and metal slats, and more. Note: The data are all measured manually, please allow 1-3cm error Due to differences in light and display, there may be some color differences, please refer to the actual item received.