Pressure sensing unit 14 having a round periphery, a central aperture 78 sized to accommodate a sensor 30 and an adhesive strip 80 that releasably overlies the aperture 78 and that can be peeled back to allow placement of the sensor 30 in the aperture 78, and then be reapplied over the aperture 78 to secure the sensor 30 within the aperture 78.