AC Infinity CLOUDLINE T4, Quiet Inline Duct Fan System with Temperature and Humidity Controller, 4-InchDescription Designed to ventilate hydroponic grow rooms, transfer heating cooling, cool AV closets, and exhaust odors. Dynamic temperature and humidity programming, with timers, grow cycles, scheduling, minimum speed. Connect with our app via Bluetooth to access advance programs, alarms, notifications, and view climate data. Mixed flow design combined with a PWM controlled EC motor for a truly quiet and energy efficient performance. Duct Size: 4