Guide rods are solid 416 Stainless Steel or 6061 Aluminum. The Guide Rod Head on both styles is 416 Stainless Steel hardened to 40 Rockwell C. The shaft on the Aluminum rod has a hard black coat of anodizing to toughen the surface. Rods have a hole drilled through them to aid in disassembly.  Note: Aluminum and Titanium Guide rods are great when you are trying to reduce weight off the front of gun. Alot of USPSA/IDPA guys, use these guide rods to make the weight requirement.