These uxcell weld nuts are perfect for metalworking projects where you need strong, permanent threaded connections. The M4-0.7mm UNC thread size is super common, and the square 8x8x4mm design provides plenty of surface area for solid welding. Made from grade 4.8 carbon steel with good weldability, they're strong enough for most applications without being overkill. Perfect for pipe furniture, tables, chairs, shelves, vehicle modifications, or trolley casters - anywhere you need to add threaded mounting points to metal surfaces. The silver finish looks clean, and the 20-piece pack gives you plenty to work with on multiple projects. Installation is straightforward - just clean the surface, tack weld to position, check alignment, then finish welding all around. Much more reliable than self-tapping screws or bolts in thin metal, and way cleaner looking than nuts and bolts sticking out everywhere.