Category 42 mainly includes theoretical and practical services provided by people, individuals or collectives involved in complex field activities; These services are provided by chemists, physicists, engineers, computer experts and lawyers.

Specifically, it includes: services provided by engineers engaged in evaluation, estimation, research and reporting in the field of science and technology; Scientific research services for medical purposes;

Group 4209 provides research and development services;

Group 42 10 provides geological survey and research and development services;

Group 42 1 1 provides chemical research services;

42 12 group provides biological research services;

Group 42 13 provides meteorological information services;

42 14 group provides testing services;

42 16 group design service;

42 17 group building design and consulting services;

42 18 group clothing design service;

4220 groups of computer programming and related services;

Group 4224 provides art appraisal services;

4227 groups of single services.

In particular, this category does not include: commercial research and development (category 35); Word processing and computer file management (category 35); Finance and financial evaluation (category 36); Mining and oil exploitation (category 37); Computer (hardware) installation and maintenance services (category 37); Services provided by professionals such as doctors, veterinarians and psychoanalysts (category 44); Medical services (category 44); Landscape design (category 44).