I use these in all my cages

https://www.amazon.com/gp/product/B07WTG2TC5

They don't get hot and I don't have any guards over them. I prefer the warm white over the cool white but that is personal preference. I use two in each of the 4' cages, three in the 5' and four in the 6' cages. The cages are stacked so I just daisy chain lights with the supplied cords through desk grommets in each cage. Each set it plugged into a power strip which is plugged into a timer.