If you are growing in an enclosure you will need to ensure there is plenty of air movement inside and these little fans are perfect for the job.
Growth Technology clip on fans are 6" in diameter and are a great little fan for providing air movement in small grow rooms or tents as they can be basically clipped onto anything and pointed in any direction you want, neatly tucked out of the way.
These clip on fans have keyhole slots in the bracket, which also allows them to be wall mounted if desired and with an adjustable head with two speed settings, it offers you greater control and direction of the flow of air in your room and amongst the plants.