The Chemical Analyzer as it appeared in Season 2
The Chemical Analyzer, is also known as the Ultraphonic Chemical Analyzer. KITT has a retractable tray with an electron scanner that could analyze the chemical properties of various materials. It could even scan fingerprints and read ballistic information off bullets and compare these with a police database. Aside from the scanning tray, the system could also analyze chemical information gathered from KITT's exterior sensors.
The Chemical Analyzer as it appeared in Season 3 and 4
("Episode 117: Chariot of Gold"; "Episode 205: Return to Cadiz")