This is the newly designed unit and will not work with older aquarium hoods imported after AUG 08
If your old Hood or ballast went out andit was made before then you will need to replace BOTH HOOD AND REPLACEMENT BALLAST
This is the Full Replacement ballast that is for the 24 gallon nano cube aquarium. This Replaces 2x36 watt units.
You must have 2x 36 Watt PC Power Compact bulbs in your existing hood for Ballast to work.
If you do not it will not work.
Simple to use just remove old unit and plug in the new,
Replacement ballast 24 g Nano Cube