The default board size is 8".
The optional pole length: 30cm. It is customizable.
Please note: the pole length does not include the 15cm gooseneck length. I do not count it in because it is used to adjust angles.

Product review from me: The round board looks good. The moss and other plants look great in the light. The timer and adjust light function are useless because I turn on the light all day and night. After using for weeks (on all the way), the moss close to the light turns out a lighter green. The other terrarium plants: most without obvious difference with those without light. The fittonia is the exception, and they grow crazily.

Sum: this lower-power LED supplement light is suitable for moss and other terrarium plants with low light needs.
Function: with timer, it can be set: 2H, 4H, 8H
The light is adjustable: 25%, 75%.
This display board with an LED grow light set is designed to display and supplement plants indoors.
The USB plug is universally compatible. You can use it with any USB charger or hub (not included) with ≥ 2A output.
Power 10W
Full spectrum white light
Color temperature: 6000-6500k
Luminous flux: 1000lm