Abstract: A wave rod for imparting curl to human hair comprises a tubular core having an integrally formed helical fin on its peripheral surface. Hair to be set is wound along the flat-bottomed helical channel formed between successive turns of the fin. A radially extending slot in the fin at the distal end of the rod permits accommodating strands of hair somewhat longer than the channel. A semi-cylindrical key integrally fixed in the distal end of the core and extending slightly therebeyond can be used to complementarily join two rods end-to-end, thereby effectively doubling the amount of channel available.