Spirometer Filter : 30mm OD

Ningbo Boya Med:Spirometer Filter 30mm Long 2217Spirometer Filter Model: 2217 Size..

Spirometer Mouthpiece : 30.5mm OD

AM Systems:Spirometer Filter 30.5mm..

Spirometer Mouthpiece w/ Filter : 30mm OD

Ningbo Boya Med:Spirometer Filter 30mm 2208Spirometer Mouthpiece with filter Size: 27.5mm I..