Product Description Specifications Made from galvanized steel, these 100mm (4") pipe clamps are sold as a pair. They fit into the top channel of a Rhino-Rack Vortex bar, and are secured in place with an M8 bolt and nyloc nut. Category: Fabrication>Clamps LTL: N MPN: SPC4 Proposition 65: Y Special Order: Y Core: N