Very effective, and accurate. THis will tell the temp of the fish tank without the electronic thermomiters which just don't really fit right in our tank. It bobs right at the waterline and doesn't disturb the fish at all.

Pros: the design allows it to float to the top of the waterline for easy viewing.

Cons: sometimes the view can become harder depending on the water's cleanliness

my fish is so content with its temperature we are both happy!!!!!!!!!!!

Pros: it is easy

Cons: none

great for telling the temperature in your fish tank

Pros: tells you the temperature

Cons: none

perfect in any size tank... great percision! knows EXACTLY what temp it is! no large electronic thermometers! perfect

Pros: works perfectly!

Cons: very small!