The invention disclosed in this application relates to a device used for guiding blown air to Spiro meters, which consists of elliptical shape at inlet to make it tight lip to all the age of patients and round shape at outlet to mechanically fit for all type of flow measuring instruments through adopters, inlet and outlet joined in aerodynamic way to minimize velocity loss in the air path, three number of groves being provided at both the sides of outer periphery of the major axis at inlet for not to slip from the mouth of the patients while measuring, made of flexible thermoplastic material so as to easily inserted in the mouth of all the age of patients.
