K.I.T.T is armored with "Tri-Helical Plasteel 1000 MBS" (Molecular Bonded Shell), a chemical coating which protects him from almost all forms of conventional firearms and explosive devices. It can only be harmed by heavy artillery and rockets. The shell protects every part of K.I.T.T, including the tires. It also protects him from fire and electricity (under a certain amperage); however, it is vulnerable to some potent acids.
The shell is actually a combination of three secret substances referred together as the "Knight Compound", developed by Wilton Knight. It has since been entrusted to the New Director of F.L.A.G, David Marks, and Charles Graiman.
This shell provides a frame tolerance of 223,000 lb (111.5 tons) and a front and rear axle suspension load of 57,000 lb (28.5 tons).