If the lamp you removed has a part number printed on it ( the UHI number) that should be the right bulb.
I can't speak specifically for pool light bulbs but most light bulbs have a standard number referring to their size, shape, connections, and overall design. For instance, your standard run of the mill house light bulb is an A-19. No matter what the wattage or who makes it, it's an A-19 bulb. You need to compare 3 things to ensure you get the right bulb; the bulb wattage, voltage, and form factor. Wattage and voltage should be printed on the bulb or with the manufacturers specifications included with the light itself. The form factor is just a matter of what it looks like. Shape, size and type (ie. halogen, LED, incandescent). The point I'm making though is that other manufacturers may make a cheaper or better one. The easiest way to locate it is with that standard number. Grainger has some good references in their catalog. I'm sure the big bulb manufacturers have cross reference material on their websites. You may want to look around a little when the thunder storms roll in and you can't sit by your pool.
