Replacement Bulb For Under Cabinet Lighting
What replacement bulb would work?


Any LED G9 120V bulb rated less than 25W. A LED bulb of around 6W probably has a brightness (see its Lumens rating) similar to a 25W Halogen. 



Glossary:


Lumens are a measure of luminous flux and are a better guide to brightness than Watts.
Watts are essentially a measure of how much heat the bulb emits, not light.