| PSC | Description
|
| 6605 | Navigational Instruments |
| 6610 | Flight Instruments |
| 6615 | Automatic Pilot Mechanisms and Airborne Gyro Components |
| 6620 | Engine Instruments |
| 6625 | Electrical and Electronic Properties Measuring and Testing Instruments |
| 6630 | Chemical Analysis Instruments |
| 6635 | Physical Properties Testing and Inspection |
| 6636 | Environmental Chambers and Related Equipment |
| 6640 | Laboratory Equipment and Supplies |
| 6645 | Time Measuring Instruments |
| 6650 | Optical Instruments, Test Equipment, Components and Accessories |
| 6655 | Geophysical Instruments |
| 6660 | Meteorological Instruments and Apparatus |
| 6665 | Hazard-detecting Instruments and Apparatus |
| 6670 | Scales and Balances |
| 6675 | Drafting, Surveying, and Mapping Instruments |
| 6680 | Liquid and Gas Flow, Liquid Level, and Mechanical Motion Measuring Instruments |
| 6685 | Pressure, Temperature, and Humidity Measuring and Controlling Instruments |
| 6695 | Combination and Miscellaneous Instruments |