Use Bidirectional Vascular Doppler MSL620V Features:

620 V 620VP TFT LCD displays the wave of the instant blood flow average velocity and strength. It prints the monitoring blood flow curve simultaneously;
Detect the blood stream status of arterial/venous by 8MHz probe;
Detect the blood flow average velocity, detect the result of fingers/toes and part of body's vein anatomies operation;
MSL620V 620VP(TFT) portable bidirectional vascular Doppler with large color LCD screen;
Built-in ARM microprocessor & real-time displays blood flow velocity waveform;
Can store 50 detected waveforms;
High-speed USB/RS -232 port, can be connected directly to computer to analyze, store, and print the waveform data;
Attention: MSL620V without thermal printer.
MSL620VP with thermal printer and can record the waveform of blood stream when it is connected with the power supply.

Cheap Bidirectional Vascular Doppler MSL620V Specification:

Executive standard: 
Classification: Safety classification: Model BF /Ⅱdevice/in side power classication.     
Water-proof degree：Common device, without function of water-proof.
       Safety degree of flammable gas:  Unsuitable to use under the flammable gas.  
Working mode: continuous work
Frequency range：Main unit ：200±80~5000±1000HZ
                  Probe ：350±80~2500±500HZ
External output：loudspeaker, single channel with earphone jack(optional) 

Emissive waveform: sine wave
Ultrasonic frequency：5.0MHz±10% 、8.0MHz ±10%
Ultrasonic frequency average intensity： < 50mW/cm2
Velocity measure range：0~100 cm /s. 
Test error：≤20%（relative error）
Overall sensitivity：> 100dB
Printing speed：40cm/min,60cm/min ,display synchronize with print.
Frequency mode display range：0.2 KHz~7.0 KHz
LCD Display：240*320dots TFT, LCD cursor indicates blood stream speed, 
double display mode for the spectrum and velocity.
Power supply: AC/DC. Input AC power: 110-240V  50Hz/60Hz
                  Output DC power: 24V/1.5A ；
Power consume：<20W；built-in Ni-MH rechargeable battery：14.4V/1600 mAh.