The Milwaukee Bolt Redlithium USB Cooling Fan is designed to provide you with the Most Powerful Airflow. Allowing you to Keep Cool, with up to 15Mph Air Speed. Paired with the Redlithium USB 3.0 Battery for Up to 6 Hours of Run-Time. The Bolt Redlithium USB Cooling Fan mounts securely on the Bolt Front and Rear Mounting Slots and allows you to customize your airflow with the included 3 Air Duct Variations. The Milwaukee Redlithium USB Battery can be recharged in the Fan via USB-C or swapped out with additional Redlithium USB Batteries (sold separately) for virtually no downtime. The Bolt Fan is compatible with all Milwaukee Bolt Safety Helmets and Bolt Hard Hats, allowing you to Secure Accessories Simultaneously.