The LG AXSVA4 is a combination of the AXSVA1 26 In. Wall Sleeve and AXRGALA01 Stamped Aluminum Rear Grille for Through-the-Wall Air Conditioners. The 26-inch wall sleeve should be securely fastened within a wall opening before installing the air conditioner. The sleeve helps bear the weight of the air conditioner while keeping it insulated and safe from dust, bugs and other debris that could get sucked into it. Inclement weather, corrosion, and any other elements cannot match the protective power of this metal sleeve. The stamped aluminum rear grille is generally used to prevent damage to the back outer coils of the air conditioner and for keeping birds and small animals from nesting in the wall sleeve.