Nissan NV3500 Slimline rear air flow kit will deliver high air flow to the middle and rear vents of your Nissan NV passenger van. This kit will increase air flow by 85% or more. It replaces the original poorly designed Nissan fabric duct system. This is an enclosed system that utilizes new high flow plastic ducts.This system comes complete with plastic overhead ducts, duct hoses, ac unit air port adapter, mounting hardware, Headliner retainers, installation instructions and youtube installation video available. This kit is very easy to install and should take only 30 minutes to install the kit. Removing and reinstalling the headliner will take additional time to complete.There is no harmful back flow your blower motor. Developed and Made in the USA.