A heated flat iron 1 includes a first elongated member 2 and a second elongated member 3 that are joined together at one end at a hinge 4. An electrical cord 5 is attached thereto and has a conventional plug (not shown) to connect the iron 1 to a conventional external electrical energy source. An upper plate 6 is attached to the first member 2, and a lower plate 7 us attached to the second member 3. The upper plate 6 comprises a longitudinally aligned groove 8, preferably including in the groove 8 a series of longitudinally spaced laterally oriented slot depressions 9. The lower plate 7 includes a set of raised ridges 10, each having a length L that is transverse to the longitudinal axis of the second member 3, a height H measured in a direction extending away from the surface of the lower plate 7, and a thickness T measured transversely to length L, where L is greater than T. The ridges 10 are aligned in a longitudinally extending row along the lower plate 7 so that the row is aligned with the groove 8 and each ridge 10 corresponds in alignment with one of the slot depressions 9. The height of the ridges 10 may be adjustably varied.