A sample checking service involves inspecting a relatively small number of items from a batch or lot, for a range of specifications such as appearance, workmanship, safety, functions, etc. prior to mass production.

It is an essential step before the manufacturing process, beginning with a physical inspection of a product sample before production begins in order to spot any defects prior to mass production. And during the sample checking process, the physical and functional characteristics of the product should also be verified against engineer drawings, a purchase order, specifications and/or other design documents, ensuring the quality of sample meets with specified requirements to avoid bulk quality problems during the manufacturing process, as well as the reliability and consistency of the manufacturing process and final product.