Basic pH tester. Comes as a complete kit, ready to use. Good for monitoring the pH of the water in your aquarium.
The biggest benefit of these compared to the cheap ones you find at places like dicksmiths/ebay is that they have replaceable heads (which is the most common point of failure) So if your head becomes clogged/damaged you don't have to replace the whole unit, only the head.
The coupon also works for all the products in the aquarium category. Valid until the end of February.
ONLY the head replacement cost $55 + postage
For that price I can buy 7x cheap one off ebay