Direct fit: MicroMedical, MIR Spiro Lab. MIR SpiroDoc, MIR SpiroBank, MIR MiniSoir and Peak tow meters

External Diameter (right) – Slight Taper from 33mm to 32mm

Internal Diameter (right) – 29mm

External Diameter (left) – 28.5mm

Internal Diameter (left)- 25mm