Aquarium Systems VisiTherm Heater 200W is a fully-submersible automatic heater for aquariums and aqua-terrariums. Temperature adjustable from 20°C to 34°C. Accurate setting in steps of 0.5°C. Hard wearing quartz glass ensuring adequate heat transfer via a high performance heating element. Dual calibration in the factory (dry and in water) in order to guarantee considerable accuracy. Suction cups provided. Control knob of the temperature. Waterproof double insulation. Visible temperature setting. Light indicates on and off cycles. Heating elements with improved insulation.