When using a Colorimeter, everyone detects different products, and different instruments have different prices, accuracy, functions, and applicable environments. Generally, products on the production line use portable Colorimeters, and desktop Colorimeters are generally used in laboratories.
The general color difference meter can be used in many industries such as plastics, coatings, automobiles, printing, textiles, food, etc. In the process of color difference meter testing, it is very important to measure whether the sample is flat. It will cause the interference of external light, resulting in wrong color difference test results. For the Colorimeter of the curved surface of small workpieces such as pipes, some special Colorimeters are needed. Therefore, when testing a Colorimeter with a curved surface, as long as the cylindrical surface can completely cover the measured aperture without light leakage. This article summarizes some small hole Colorimeters that can measure curved surfaces.

| brand | model | Measuring caliber |
| San Enchi | NR60CP | 4MM/8MM |
| San Enchi | SC-10 | 4mm |
| San Enchi | NR110 | 4mm |
| San Enchi | NR10QC | 4mm |
| Weaver | WF32-4MM | 4mm |
| Weaver | WR10QC | 4mm |
| Weaver | WR18 | 4MM/8MM |
| Kim Joon | JZ-610 | 4mm |
| Kim Joon | JZ-650 | 4MM/8MM |