Allstar 1/4 inch I.D - 1 inch O.D Steel Back Up Washer (Pack of 100) features washers that have a 1/4 inch i.d. with a 1 inch o.d. They are sold as one set of 100 pieces. The back-up washers provide added strength when fastening panels together or when resecuring damaged panels. They are perfect for use around the shop or race track. Several other popular sizes are also available and are sold separately. They are backed by a 90-day limited factory warranty.