CALORITECH CX Series Screwplug Immersion Heaters are used primarily for water heating in tanks or vessels and have brass screwplugs with NPT-style threads and copper sheath element(s). Heaters are available with factory-installed thermostats to control the liquid temperatures. These heaters are designed to be fully immersed in liquid at all times. Application-Screwplug heaters are primarily used to heat liquids in tanks or vessels. To do so safely and reliably, the heating elements must remain fully immersed in the liquid. Liquids such as water, oils, trichloroethylene, etc. can be heated through natural convection currents created by the immersed elements. Although electricity costs are generally higher than gas or oil, a CALORITECH immersion heater is often the best choice. The electric heater provides close to 100% efficiency, is safer and easier to control and is usually cheaper to install. Terminal Block Simplifies Wiring - All thermostat-equipped screwplug heaters with moisture or explosion-proof housings feature a convenient terminal block mounted to a slide-out trolley. This unique CALORITECH feature simplifies installation and reduces maintenance. Color: Silver/Red/Copper.