These in-line fuel filters are constructed from high-quality aluminum. Each filter is made up of two threaded aluminum halves that seperate for easy cleaning. Inside the filter is a mesh screen that can filter particles down to 130 microns in size. To seal against fuel leakage, each filter contains a rubber o-ring. Running an in-line fuel filter will insure that your RC vehicle's engine is receiving the cleanest fuel possible which will help to extend its life. In-line fuel filters come one per package.