Ceiling Lay-In Plaque Diffuser 24X24 with Insulation - DPLCeiling Lay In Plaque Diffuser 24X24 with Insulation DPL (Old DPL) Click here for SUBMITTAL Click here for Performance Tables (CFMs, etc) The DPL modular diffuser is designed for seamless integration into ceiling lay in grid systems, offering high efficiency airflow and superior durability. Its 24 x 24 design includes a high performance insulated distribution box and a round neck for easy, flexible duct connection. The addition of an air shock plate