EGC5 F2320FF - Filter Frame - Aluminum Egg-Crate Return Grille - 20" F23 Lay-InKrueger EGC5 F2320FF Filter Frame Aluminum Egg Crate Return Grille 20" F23 Lay In The EGC5 egg crate return grilles are designed to fit common commercial applications were the architect requires a return grille without bars on the face and with limited sight through the grille. The EGC5 offers 1 2 x 1 2 x 1 2 aluminum cube core and 1 1 4 flange. The EGC5 cube core design maximizes the free area making the EGC5 an excellent choice for applications