BSMI respirometer (Bangladeshi)

Made in Bangladesh
-Product Type: 3-Ball Lung Exerciser
-Usage: Instructions For Use: Place the device at mouth level, exhale normally before inhaling, Inhale thoroughly until lifting the three balls (if, possible), Hold inspiration as long as possible., Remove the mouthpiece and exhale., Repeat the process.
-Recommended Usage: Follow doctor’s advice.
-Warranty: No Warranty