The original Spear unit is lined with an aerogel insulation layer. Of which Discovery Channel thought it was interesting enough to use that same insulation to try and protect a house in the case of a wildfire. Experiments with Aerogel are unique in a lot of ways. If you were to google Aerogel insulation and sort through some Youtube videos, you’d see people putting objects on one side and a flame on the other to see which melts first. Steel materials melt before Aerogel does. There is a video of a man putting a quarter on it with his hand under it, the quarter melts with a flame while the man can hold it. It has a fantastic insulation value, but it also has other strengths like Electromagnetic Shielding and Fire Tolerance.