10 cm
Here are answers to your concerns
Q: Is this product suitable for grow tents?
A: YES. Know the size of the ducting before choosing the fan as well. Our inline duct fan comes with the option of different sizes.
Q: Can it be used indoors?
A: YES. It helps a lot with air circulation, as well as with odors and dampness. You'll have no problem finding one that suits your living rooms, studios, and electronic equipment rooms. Very quiet too.
Q: Is this fan durable?
A: YES. Our fan can reach 30,000 hours of continuous operation. Energy efficient EC-motor ensures ultra stable operation.