This is a new 500W, 120V bulb for pool light replacement that is a flood light style bulb (similar to R40 bulb).  This bulb should fit a wide range of pool fixtures (excluding spa fixtures) and is compatible with 120 V pool light systems.  Please note:  Make sure your pool fixture is not leaking.   It is best to test with light out of water prior to reinstalling light underwater to make sure your fixture or gasket has not failed and that light is receiving voltage.  Thank you.  (Note: Not responsible for incorrect installation or damaged fixtures.)