We are the genuine manufacturers of this product and we manufacture this product at our manufacturing facility in new delhi specifications: recommended tidal volume: upto ~ 1500ml temperature (iso 9360) o vt 250ml: 32 c o vt 500ml: 32 c o vt 750ml: 32 c o vt 1000ml: 32 c absolute humidity (500ml vt, 20bpm): 30. 6mg h2ol dead space: 45ml bacterial filtration efficiency: 99. 99674% virus filtration efficiency: 99. 99362% resistance to flow (iso 9360) o 30lmin, 60lmin,