This document discusses different types of inventory management systems suitable for different production environments. It states that a fill-up system is suitable for products with low demand variation with a COV between 0 and 2, while a sequential system works best for high mix production with low batch sizes and a COV greater than 2.5. The document recommends using a fill-up system for low COV products and a sequential system for high COV products in an environment with a mix of product types exhibiting different COV levels.