This means that you'll be able to search for NAICS codes directly (if that's your jam). We'll do the math; let's make better data on public procurement together.
Quality Control Services: Tractors
Possible NAICS Codes
811310 – Commercial and Industrial Machinery and Equipment (except Automotive and Electronic) Repair and Maintenance
811111 – General Automotive Repair
336611 – Ship Building and Repairing
336111 – Automobile Manufacturing
333111 – Farm Machinery and Equipment Manufacturing