Made from clear triple hardened Pyrex these tubes will last a lifetime without discoloring. Watch your coolant flow is not only a eye catcher but a functional item. Notice in advance any problems that may be arising in your engine before it's too late. These are available with Red, Blue, Green or white LED lighting kits to match any coolant color you may want to use. All Killerglass items are made in limited quantities so don't wait. www.killerglass.com