The slimline, vertical VL500 Lossnay Fresh Air Heat Recovery Ventilation System provides the ultimate in energy efficient ventilation to ensure your home has a constant supply of healthy, fresh air. With its small upright footprint, it can be placed in the garage or a utility cupboard and is not limited to an in-roof installation. Outside air and return air ducts are located on the right side. Air volume: 139l/s (Fan Speed 4). (WxDxH, mm) 725 x 556 x 632. Weight: 39kg. Duct size: 157mm. Operated by the simple to use backlit LCD controller located on the right side with Automatic Summer Bypass.