Features: HIGH STRENGTH MATERIAL - forged by heat treated high tensile alloy steel, and the Mandrel Piece Riveter Tip nose is strong, durable and anti-rust. MARKED STURDY CASE - comes with a colorful sturdy plastic case to store and classify the size of various chucks. VARIOUS SIZE OPTIONAL - metric M3, M4, M5, M6, M8, M10 and M12 all together 7 different sizes for choose. ECONOMICAL - Save money and replace the rivet nut mandrel instead of buying a new rivet! UNIVERSAL FIT - Fits many standard nut riveters. Specification: Size : M3 / M4 / M5 / M6 / M8 / M10 / M12 (optional) Material: alloy steel Quantity: 1 package Storage: colored Labeled Plastic case Packing list: 1 * M3 Chuck 1 * Storage box