C.S. Osborne Set of 25 Black Grommets And Plain Washers. Brass material with dull black finish grommets and washers. You will receive 25 grommets and 25 washers. Made in USA. Size : 4 Diameter of hole when set : 1/2" Set these grommets with one of the following tools: C.S. Osborne Plain Washer Grommet Setter, C.S. Osborne Grommet Kits or Press-N-Snap Tool. Punch holes before setting grommets with one of the following tools: C.S. Osborne Drive Hole Punch, C.S. Osborne Revolving Hole Punch or Screw Hole Punch.