Air Filter Injen Hydro Shield 15cm x 12cm Injen Hydro Shield Pre Filter Universal Black water repellant Pre Air Filter Injen Hydro Shield 15cm x 12cm INJEN HYDRO SHIELD PUT TO THE TEST!! YouTube. Introducing a colorful piece of mind For that added protection during those unsure moments, Injen Technologys HYDRO SHIELD PRE FILTERS are race proven material manufactured from highly durable polyester. Uniform micron openings allow the filtering of debris . 005 or larger. The HYDRO SHIELD PRE FILTERS are factory treated using an embedded hydrophobic process, which offers consistent airflow, water repellency and maintains horsepower gains. (Please note that this item is water repellent, not water proof) Snug and secure, the HYDRO SHIELD PRE FILTERS comes in various sizes and colors. Everyone should practice safe driving! KEY FEATURES: Available in Black Water Repellent Outer Coating Consistent Air Flow