Airking In Line Air FilterThe Airking in line air filter adds a little peace of mind when filling your air rifle. All Airking compressors already have an internal moister and particle separator but this gadget allows you to filter out any last remaining moisture or debris. Plus, its always a benefit if you can directly and easily inspect a filter after charging. Please also know this filter is compatible with other filling devices. It utilizes a male foster fitting on one end