Specification:  Automatic thermostat.  Temperature control range: 20 ~ 34°C.  Material: High quanlity quartz glass.  Voltage: 220V.  Frequency: 50Hz.  Wattage: 50W /100W / 200W / 300W / 500W.  Color: Black.  Power: Heater Length x Cable Length x Recommended Aquarium.  50W: 230mm x 1.3 M x up to 50 litres.  100W: 270mm x 1.3 M x 50 to 100 litres.  200W: 330mm x 3 M x 150 to 200 litres.  300W: 390mm x 3 M x 200 to 300 litres.  500W: 470mm x 3 M x 300 to 500 litres.     Features:  - 3 M Cable (200/300/500W).  - Automatic thermostat.  - Precise & Reliable temperature control.  - Fully submersible.  - Double seal waterproof.  - Ideal for Freshwater or Saltwater.  - Easy to set required temperature with temperature scale.  - High Quality Components.  - High temperature resistance and wear resistance.  - All heaters come supplied with 2 x sucker holder clips.     Using:  1. The heating rod of the fish tank must be completely immersed in water to avoid dry burning.  2.When the power supply of the heating rod is pulled out, it needs to continue cooling for more than half an hour before the water surface can be taken out, so as to prevent the waste heat of the rod from producing high temperature and causing serious damage to the heating rod. (don't forget when changing water) 3.If the hand wants to go into water, it must cut off the power supply of all equipment in the cylinder (filter, heating rod, aquarium lamp) to ensure safety. Do not use wet hand to plug in the power supply.  4 Before using this product, please ensure that the aworking voltage indicated on the product is in accordance with the main voltage. It is recommended that the power supply of the product be equipped with a short-circuit leakage protection switch whose rated work current is less than 30 mA.     Note:  Glass products, do not knock or fall.  The heating rod must be cooled before it can be put in or taken out of the tank.     Packing:  1 x Aquarium Quartz Heater.  1 x UK Adapter.  2 x Sucker Holder Clips