"THE INTERNAL FUEL WIRES ARE RECESSED TWO INCHES ON ONE END OF THE ROD. THIS RECESS IS AN INTEGRAL SAFETY FEATURE, PREVENTING THE ROD FROM BURNING BA CK TO THE TORCH. THE INTERIOR WIRES ARE ARRANGED IN A CIRCULAR PATTERN WITH A CLEAR CENTER OXYGEN PATH. THE WIRES ARE RETAINED WITHIN THE TUBE BY CIRCULAR CRIMPS. OD FROM BURNING CUTTING RODS,3/8"" X 36"", 25 ROD BOX"