All Star Black 1/4" to 3/8" Grip Range Aluminum Mandrel (250 pieces) Small Head Rivets feature aluminum mandrel and black finish head rivets on rivet head. Rivets have a range of 1/4" to 3/8". Sold as a pair of 250. Ideal for use in shops and race tracks. Some other popular sizes and colors are sold separately. 90 days limited factory warranty.