Hot and cold air functions work. I haven't used it, so I'm not sure. Judging by the filter in the back, it doesn't seem to have been used much, but this is just my subjective opinion, so please understand. 【Salon-Quality Finish】 Adopting advanced high-concentration negative ion technology, it releases up to 200 million high-concentration negative ions with each use. Dramatically reduces static electricity and friction, controlling frizz and tangles. The hair dryer inhibits the growth of bacteria, attracts moisture from the air, and forms a protective film on the hair's surface. This retains moisture while protecting the hair color from sunlight, restoring natural shine and elasticity. For those who often dye their hair, it also has a function to prevent fading, reducing damage to the hair. Loved by hairdressers, you can experience professional-level care effects. 【Ultimate Quick Drying Power】 Adopting the latest HPD motor and streamlined airflow design, it rotates at an astonishing speed of 200,000 rpm per minute, with a maximum wind speed of 3.6 m/s. Instantly removes moisture from the hair's surface, drying hair in the shortest time possible. Achieves 5 times the efficiency of commercially available high-volume hair dryers! Short hair dries in 1-2 minutes, medium hair in 3-5 minutes, and long hair in 5-6 minutes, and men can dry their hair in under a minute. 【3-Stage Wind Speed Adjustment】 Equipped with 3 modes: cold air, warm air, and hot air. Also equipped with an NTC smart temperature control sensor, it outputs a constant temperature with precise temperature control technology of 110 times per second, automatically adjusting the temperature according to different environments and hair conditions, preventing excessive heating and damage, and protecting the hair from being damaged by high temperatures. The hair dryer is equipped with an overheat protection device, and if the temperature rises after prolonged use, the power will automatically turn off. 【Multi-functional】 Ergonomic handle design provides a natural and comfortable grip experience. Popular T-shaped design! Foldable and compact body. Weighs only 299g! 【Product Details】 Brand: Alloom Product Type: Hair Dryer Product Name: Hair Dryer High Air Volume Quick Drying 【Salon Exclusive】 T-shaped Design Manufacturer: Shenzhen Jiuyangzhou Industrial Co.,Ltd. Product Number: XS-1000