I bought this by accident not realizing the headers I bought came already with a roll of this exact product. I will say it absolutely works and doesn't discolor like fiberglass wraps. Although I didn't put an infrared thermometer on it, it at least insulates the heat on the hand. I haven't noticed any higher oil temperatures and my manifolds wrap around the oil pan (Subaru engine, original manifolds had fiberglass insulation). It was pretty easy to cut and install, but it took a bit (like any package). WEAR GLOVES. Some will say you don't need them, these people are crazy. Even with nitrile gloves on, I was picking fiberglass out of my hands for at least a week most of the installation. If possible, avoid walking on your hands. You will be very tempted as it is like cloth until you do this. Then he will simply shower your hands with splinters of fiberglass. Even a mask might be a good idea as I blew some of it out of my nose. I would also suggest using stainless steel zip ties and consider using their tool to tighten them. I used some needles and a flathead screwdriver and it was pretty annoying. I'm sure their tool works a little better and makes the product look neater.