This Class Includes :
3312.01 — Repair and maintenance of industrial machinery and equipment like sharpening or installing commercial and industrial machinery blades and saws; the provision of welding (e.g. automotive, general) repair services; the repair of agricultural and other heavy and industrial machinery and equipment (e.g. forklifts and other materials handling equipment, machine tools, commercial refrigeration equipment, construction equipment and mining machinery)
3312.02 — Repair and maintenance of non-automotive engines, e.g. ship or rail engines
3312.03 — Repair and maintenance of pumps and related equipment
3312.04 — Repair and maintenance of fluid power equipment
3312.05 — Repair of valves
3312.06 — Repair of gearing and driving elements
3312.07 — Repair and maintenance of industrial process furnaces
3312.08 — Repair and maintenance of materials handling equipment
3312.09 — Repair and maintenance of commercial refrigeration equipment and air purifying equipment
3312.1 — Repair and maintenance of commercial-type general-purpose machinery
3312.11 — Repair of other power-driven hand-tools
3312.12 — Repair and maintenance of metal cutting and metal forming machine tools and accessories
3312.13 — Repair and maintenance of other machine tools
3312.14 — Repair and maintenance of agricultural tractors
3312.15 — Repair and maintenance of agricultural machinery and forestry and logging machinery
3312.16 — Repair and maintenance of metallurgy machinery
3312.18 — Repair and maintenance of food, beverage, and tobacco processing machinery
3312.19 — Repair and maintenance of textile apparel, and leather production machinery
3312.2 — Repair and maintenance of papermaking machinery
3312.21 — Repair and maintenance of other special-purpose machinery
3312.22 — Repair and maintenance of weighing equipment
3312.23 — Repair and maintenance of vending machines
3312.24 — Repair and maintenance of cash registers
3312.25 — Repair and maintenance of photocopy machines
3312.26 — Repair of calculators, electronic or not
3312.27 — Repair of typewriters

This Class Includes :
3313.01 — Repair and maintenance of the measuring, testing, navigating and control equipment such as:
• Aircraft engine instruments
• Automotive emissions testing equipment
• Meteorological instruments
• Physical, electrical and chemical properties testing and inspection equipment
• Surveying instruments
• Radiation detection and monitoring instruments
3313.02 — Repair and maintenance of irradiation, electromedical and electrotherapeutic equipment such as:
• Magnetic resonance imaging equipment
• Medical ultrasound equipment
• Pacemakers
• Hearing aids
• Electrocardiographs
• Electromedical endoscopic equipment
• Irradiation apparatus
3313.03 — Repair and maintenance of optical instruments and equipment, if the use is mainly commercial, such as:
• Binoculars
• Microscopes (except electron and proton microscopes)
• Telescopes
• Prisms and lenses (except ophthalmic)
• Photographic equipment

This Class Includes :
3314.01 — Repair and maintenance of power, distribution, and specialty transformers
3314.02 — Repair and maintenance of electric motors, generators, and motor generator sets
3314.03 — Repair and maintenance of switchgear and switchboard apparatus
3314.04 — Repair and maintenance of relays and industrial controls
3314.05 — Repair and maintenance of primary and storage batteries
3314.06 — Repair and maintenance of electric lighting equipment
3314.07 — Repair and maintenance of current—carrying wiring devices and non current—carrying wiring devices for wiring electrical circuits

This Class Includes :
3319.01 — Repair of fishing nets, including mending
3319.02 — Repair or ropes, riggings, canvas and tarps
3319.03 — Repair of fertilizer and chemical storage bags
3319.04 — Repair or reconditioning of wooden pallets, shipping drums or barrels, and similar items
3319.05 — Repair of pinball machines and other coin—operated games
3319.06 — Restoring of organs and other historical musical instruments