Spirometer is used as a respiratory exerciser for lungs, some picks from Amazon
Lung Exerciser - 3-Ball Deep Lung Breathing Exerciser Spirometer Breathing Balls Safe Breath Exercise System Respirometer : Amazon.co.uk: Health & Personal Care
OXY WAY Spirometer/ Respirometer/ Breathing/ Lung Exerciser 3-Ball Respiratory Exerciser Price in India - Buy OXY WAY Spirometer/ Respirometer/ Breathing/ Lung Exerciser 3-Ball Respiratory Exerciser online at Flipkart.com