Model 427 is made in several different versions with different attenuation from 0.5 dB/cm*MHz – 0.7 dB/cm*MHz. The attenuation is documented.
The speed of sound is either 1500 m/sec or 1540m/sec +/- 15 m/sec from 20 - 25 degrees C. 1500 m/sec is recommended.
Tubes are either C-flex or polyethylene. C-flex is recommended. The C-flex tubes are 8 mm, 4 mm or 2 mm with a wall of 0.8 mm. The polyethylene tubes are 0.2 mm wall, 6.6 mm or 3.6 mm inner diameter. All tubes are mounted at an angle of 30 degree.
Backscattering is not specified.
Density is1045 kg/m3 for the 1540 m/sec version and 1020 kg/m3 for the 1500 m/sec version.
Maximum pressure: 0.50 m H2O for PE-tubes version and 4 m H2O for C-flex version.
Flow range depends on tubes. Max. flow ~ 100 cm/sec.
Distance to deepest tube is 20 cm.