| 331 | Unit Coolers | Company Product |
| 332 | Unions | Company Product |
| 333 | Underwater Welding Equipment | Company Product |
| 334 | Uniforms | Company Product |
| 335 | Underwater Services | Company Product |
| 336 | Underwater Lights | Company Product |
| 337 | Underwater Photographers | Company Product |
| 338 | Underwater Ndt Services | Company Product |
| 339 | Underwater Hydraulic Tools | Company Product |
| 340 | Underwater Cameras | Company Product |
| 341 | Undergarments Manufacturers & Wholesalers | Company Product |
| 342 | Undercarpet Power Cable Systems | Company Product |
| 343 | Underground Cable Cover Plates | Company Product |
| 344 | Umbrellas Supplies | Company Product |
| 345 | Umbrellas Manufacturers & Wholesalers | Company Product |
| 346 | Ultrasonic Welding Equipment | Company Product |
| 347 | Uncoilers | Company Product |
| 348 | Ultrasound Medical Equipment | Company Product |
| 349 | Ultrasonic Sensors | Company Product |
| 350 | Ultrasonic Power Supplies | Company Product |
| 351 | Ultrasonic Tank Meters | Company Product |
| 352 | Ultrasonic Thickness Indicators | Company Product |
| 353 | Ultrasonic Polishing Equipment | Company Product |
| 354 | Ultrasonic Flowmeters | Company Product |
| 355 | Ultrasonic Cleaning Equipment | Company Product |
| 356 | Ultrasonic Equipment & Supplies | Company Product |
| 357 | Ultraviolet Radiometers | Company Product |
| 358 | Ultraviolet Sterilizers | Company Product |
| 359 | Ultrasonic Generators | Company Product |
| 360 | Ultraviolet Purifiers | Company Product |