HIGH QUALITY MATERIAL:made of high quality carbon steel,the roofing nails are very hard and sharp enough to keep straight when you hammer them in,can be used at various types of materials, including wood and drywall,Suitable for use in most types of concrete walls, brick, plaster and pinePRODUCT SIZE: The Thumbtacks Have a Diameter of 9.5 Millimeters and a Steel Tip Length of 9.5 Millimeters. The Ball Head and Sharp Steel Tip Make Them Suitable for Inserting Into Cork, Walls, and Other SurfacesLARGE QUANTITY:You will get 1000 pieces strong drawing pins are stored in a plastic box, large quantity can meet your various needs, can be used for a long timeWIDE APPLICATION: Round pins for pinboard is used to organize notes or reminders on the cork board, mark locations on the map, etc. Good for pinning your work papers, craft work, photos etc. Suitable for home, school and office useEASY TO INSTALL:You could just clamp upholstery pins with a plier then using a hammer to hammer these picture tacks into the corkboard or the edge of the sofa and soft bed easily. And do not hammer with bare hands for it may cause bending shanks