The Mini Aquarium Heating Units are designed to increase temperature slightly above room temperature and are idea for small goldfih tanks and other less temperature sensitive fish.
Typical tempeature increases
7.5 W 14.5 X 5.8 cm 8 l approx 2.5° C above room
7.5 W 14.5 X 5.8 cm 20 l approx 2° C above room
15 W 15.8 x 6.2 cm 20 l approx 2.5° C above room
15 W 15.8 x 6.2 cm 40 l approx 2° C above room | 
