21Pcs Rivet Nut Tools Simple Installation Hand Rivet Nut Head Manual Riveter Tool Hand Nuts Riveter Rivnut Tool for M3 M4 M5 M6 M8 M10 Nuts. Feature: Replaceable Mandrel Head for Versatile Use, Easy Assembly and Use, Cost-Effective Solution, Convenient Storage Bag Included, and Reliable. Specification: Origin Mainland China, DIY Supplies Metalworking, Material Alloy Steel, Rivet head size as shown in the picture, Product packaging size about 200x100x50mm. Includes 1 X Rivet Head, 20 X Rivets, 1 X Storage Bag.