Ballistics Brothers Precision Cooler Pro! This is a micro-USB powered fan that cools your chamber and barrel. This fan significantly decreases the time it takes for a rifle barrel to cool down. My testing has found that this can decrease the time it takes to cool off a hot barrel from 10-15 minutes to just 1-3. We have recently started printing these in ORANGE for greater visibility as well as to double as a chamber flag. Unlike homemade barrel fans that use small loud air mattress pumps, this is relatively quiet and easy to use. All you do is plug it in to any USB power source (power source and micro-USB cable not included). This will also outperform and outlast the MagnetoSpeed RifleKuhl that uses a tiny cheap quadcopter fan. Competitor fans put out about 5-6 mph. Our Precision Cooler Pro puts out 12.2 mph! 0.736 CFM compared to the competition at about 0.134 CFM!!! This will fit any chamber that is at least 1.8 inches deep and 0.4 inches wide. I source the fans from another manufacturer and then print a housing for it to work in a rifle. The specs for the fans are below: Rated Voltage: DC 24V Current: 0.1A Power: 2.4W Speed: 5500PRM Air Pressure: 16.28mmH₂O Airflow: 3.23CFM Noise: 40dBA This is custom designed, 3d printed and assembled in the USA personally by me. If you are not 100% satisfied with your purchase, please message me and we will work something out. This comes with a 30-day moneyback guarantee. Packaging may vary. SCOPE, RIFLE, USB CABLE AND POWER SUPPLY ARE NOT INCLUDED! Disclaimer: Ballistics Brothers LLC. is not affiliated with any brand or manufacturer. All products that we sell are designed and built by us in the USA.