The unstoppable rise of Isomax Acoustic Fans has been one of the major success stories of recent years in the UK indoor gardening market. With a reassuringly robust design and high quality components, each of the four units will comfortably help you overcome the challenges of extracting air from a modern grow room. Key features include the innovative baffle and acoustic lined chamber (much like a very large silencer) that successfully combine to minimise overall noise output whilst allowing for movement of gargantuan amounts of air. Both of the two smaller fans also provide convenient inbuilt fan speed controllers, offering even more value for money! Very highly recommended!