BRAND NEW Great for ponds and both Fresh Water and Marine Water aquariums, aquaculture, terrariums & hydroponic systems! Fully Submersible Aquarium Heater Strong Quartz Glass Aquarium Fish Tank Heater, Suitable for most aquarium sizes. Temperature can be adjusted between 61°F~93°F.  Auto shut off to maintain constant and stable temperatures for your aquatic life. Explosion-proof Shatterproof Shield-proof Design: Thanks to its high quality Quartz Glass material and its Protective Sleeve, Lineba aquarium heater is shatter resistant & more durable than conventional glass heaters Set and adjust the desired temperature with the use of the Temperature Controller on the top.Maximum strength Quartz Silica Tube is shatter resistant & more durable than conventional glass heaters.Durable Plastic Outer Sleeve. There is a durable thick plastic outer housing wrapping up the glass tube. Acting as a buffer between your fish and the hot heater with Non-conductive plastic outer sleeve so fish/turtle/plants can’t be burnt. Once installed they form a pressure fit around the quartz glass housing and the outer protective housing.Thermostatic Control This heater can automatically control the temperature. It will automatically turn off as the temperature rises above the internal setting you choose, and turns back on like clockwork once it is needed.