3 RETURN AIR PATHWAYS – Save time, energy, and money with Tamarack Ventilation door transfer grilles. These user-friendly door vents eliminate air pressure imbalances in the home and increase your HVAC system’s efficiency. They also reduce moisture in the bathroom and are a simple way to improve the quality of the air you breathe in your home. BALANCED AIR PRESSURE – Even with closed doors, the vents balance air pressure and prevent uneven room temperatures. The return air pathway decreases moisture in bathrooms and preserves energy throughout any building or home. The balance ensures that the inside temperature, humidity, air quality, and energy consumption levels stay right where you want them. COST-EFFICIENT AIRFLOW – Great for Combustion Appliance Zones, Tamarack Ventilation vents extend the life of any HVAC system. Saving money on cooling and heating is a breeze with these 3-pack of Tamarack Return Air Pathways. Plus, this item is BPI Listed by the Better Performance Institute. LONG-LASTING & MADE IN USA – Made with durable, high-impact ABS plastic, our vents are covered by a lifetime manufacturer's warranty. While air flows freely between rooms, the internal baffle material prevents any increased transmission of light and sound through the vent/grille. With this 3-pack of RAPs, you’ll have quality airflow for the long haul. EASY DOOR INSTALLATION – No need to install crossover or jump ducts with this convenient in-door vent. The kit includes a template for cutting exact unit measurements. This model is made for 1 ⅜ inch thick hollow core doors. On average, we spend 90% of our time indoors, but indoor air quality is typically 2-5 times more polluted than outdoor air. Tamarack Door Return Air Pathways (DRAPs, for short) are unique transfer grilles designed to maintain adequate air flow between rooms and eliminate pressure imbalances. Our RAPs are a simple and inexpensive way to improve indoor air quality, relieve rooms of hot and cold spots, and reduce strain on AC systems. Most importantly, installing RAPs improves energy efficiency and provides homeowners with significant savings on both cooling and heating. Specifications: Grille Length: 25" Grille Width: 4.75" Duct Size: 4" x 24" Material: ABS