I still recommend the walmart kind but it is more because I refuse to buy anything made by Flukers. I won't get into why here because if I did, I would have to pull my own post.
Any hooded ceramic fixture will do though sitting on top of a screen, they don't project heat downward quite as well, as the screen will diffuse the heat somewhat. So higher watt may be necessary. It is all a matter of fiddling with bulb wattages and raising and lowering the basking spot till you get the basking spot a temp between 95-115F, with the higher end better for babies. A wide tapering basking spot works best, as it allows more surface area to be exposed to the bulb and more room for your dragon to 'spread out' and heat up. Having lower slops and levels of the basking are work great as they give more areas for the dragon to choose that can have varying temps.
In observing my bearded dragons, I do notice they take the warmer temps first thing in the morning and after they eat, and moving to cooler basking areas afterwards, in between stomping all over the cage.
Another reason why I recommend an adult cage of at least 4'x2' in size, with 5'x2' being better for a single adult. Gives them much more room to move around and get exercise, especially if taking them out of the cage and letting them run around in a dragon safe area of your home, isn't possible on a regular basis.
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PHLdyPayne