Ventilating fan 1.Combingperfectlywitn centrifugal wind wheel and voluted crust,maximumly achieving larger exhaust volume and lower noise. 2.Built-in anti-reflux panel, one-way opening and closing.Better tightness. 3.Specially installation way with plastic buckle , making thewind duct' installation more convenient. 4.No welding process of metalframemakes more compact and refined. Model Hole SizeRate voltage&frequencePowerExhaust volumeWind pressureLJBPT15-23A260x260mm220V & 50HZ31W200 m³/h100 PaLJBPT15-34A260x260mm 220V & 50HZ 31W260 m³/h160 Pa .