A cartridge heater provides concentrated heat in a limited space. These heaters are typically used for heating metal parts. Designed for easy installation, cartridge heaters are made smaller than their nominal diameter. However, they can be can be found in a variety of compact sizes in low-watt or high-watt density options. Choose a low-watt density cartridge heater for packaging, heat sealing, laminating, refrigeration and hot-melt reservoirs or nozzles. High-watt density cartridge heaters are used in plastic extruders, hot stamping, medical equipment, food processing, hot-runner molds and other plastic molding equipment.