Where can I buy a spirometer?
Med-Tech & Design Associates International offers a variety of different types of spirometers.
https://4medtech.com/product-category/spirometers/
NDD EasyOne Air

Being a intergration with OccuPlus the NDD EasyOne® Air is a flexible, accurate and proven spirometry solution designed for healthcare providers large and small. Utilizing TrueFlow™ technology, this portable spirometer delivers reliable results without the need for calibration to ensure lifetime worry-free operation.
$1,955.00 $1,899.00
https://4medtech.com/shop/spirometers/easyone-air-3/
MSG SpiroPlus USB Spirometer

Robust, lightweight, User-friendly with state of the art technology. This USB Spirometer Meets & Exceeds SANS-451 Standards and intergrates with Occuplus software.
USB Powered PC/Software driven
Incentive graphics for children
Peak flow sensor
Patient database
Email/Jpeg test results
Displays flow/volume and volume/time graphs
Determines FVC and FEV1, FEV1/FVC, and other indices, Automated calibration check using 3-liter syringe with 1/2-, 3-, and 6-second flows
Incudes interpretations and numerous predicted sets
$1,699.00
https://4medtech.com/shop/spirometers/msg-spiroplus-usb-spirometer/