Arrow's medium aluminum rivets come 20 to a set. These rivets have a diameter of 5/32-inch and a grip range of 1/4-inch. Use these aluminum rivets for lighter weight jobs and materials, such as aluminum, fabrics, plastics, leather, etc. The 5/32-inch diameter is the middle size of three available. (The other two are 1/8-inch and 3/16-inch; the strength necessary for the job will determine the rivet diameter needed.) The 1/4-inch grip range is the middle of three available options. (The other two are 1/8-inch and 1/2-inch.) Determine the rivet grip range by the thickness of the materials being fastened. Be sure to use washers when joining soft materials or when an existing hole is oversize.