Stainless steel sleeve insert with integrated weld-on nut for the StyleFetish modular furniture system. Slides into square steel tubing to create a threaded mounting point at any position along the tube length. Enables bolt-through attachment of crossbars, restraint carriers, and accessory modules without drilling or welding on site. Precision-machined to exact tolerances for a snug, rattle-free fit inside 30×30 mm steel tubing. German-manufactured from heavy-gauge stainless steel for lasting structural integrity.