exhaust your ABS fumes outside with this 3" hose adaptor. The fan goes on the outside of your case and connects to the hose with a ziptie. The other end will ziptie to a 90 degree connector on a 2" PVC connector for venting outside. 72mm fans are often found on power supplies for computers. Make sure to avoid the capacitors if you take a power supply apart! They can hold a charge for a very long time and can be very dangerous!print at .2mm no support 15% infil