Features 1、SPECIFICATIONS: The size of a single gasbag is 19 x 8cm, with 0.5L capacity and 22mm port inner diameter, ensuring seamless and reliable connection, and preventing gas leakage. 2、NBR MATERIAL: These breathing training bags are made of excellent NBR material, which has good airtightness, oil and wear resistance, good heat resistance, and strong adhesion. 3、PRODUCT USE: These NBR bags are suitable for breath training, increasing lung strength and capacity, increasing O2 uptake in important organs, and enhancing physical endurance. 4、REUSABLE AND DURABLE: These NBR rubber bags are reusable and durable, effectively reducing costs, making them easy to use and replace at any time, and meeting more usage needs. 5、APPLICATIONS: This kit includes 5pcs NBR gasbags, suitable for laboratory, hospital and industrial use, can be easily installed on instruments, providing convenience for work and experimentation. Specification Item Type: Breathing Bags Material: NBR Port Inner Diameter: Approx. 22mm / 0.87in Bag Size: Approx. 19 x 8cm / 7.5 x 3.1in Package List 5 x Gas Bags