Amazon.com: Breathing Exercise Device for Lungs - Lung Exerciser Device with Adjustable Resistance - Increase Lung Capacity, Improve Sleep & Physical Performance : Health & Household
PowerLung Trainer PLT-K100, Sage Green
Breathing Trainer Lung Respirator Exercise Tool Silicone Expiratory Training Equipment Lung Capacity Training Device H8WD| | - AliExpress
Amazon.com: POWERbreathe - Breathing Exercise Device for Lungs, Breathing Trainer and Therapy Tool to Strengthen Breathing Muscles and Help Lung Capacity, Inspiratory Muscle Trainer - Blue, Medium Resistance : Health & Household