Comes with magnets to mount on your tank glass. High-End Accuracy- (+/-) 1.5 F
Notes from Penny:
Reef systems should be kept at 78 degrees F (76 Min & 80 MAX). We never want to rely solely on electronic controllers. These inexpensive yet super accurate thermometers will give you piece of mind. You should calibrate your heaters or controller based on what your glass thermometer reads.