POCKET DOPPLERS

The Model 840 is designed for the doctor who needs an instrument he or she can easily carry in a coat pocket.  Despite its small size, the sensitivity is only somewhat less than that of our larger models.  The difference in depth of penetration is about 25% less.  You will find this Doppler very convenient for use in the recovery room or on the ward.  Headphones let you hear better than a speaker does.

The Model 840 performs very well at the groin crease, the posterior tibial at the ankle, the dorsalis pedis, digits, the supra-orbital and the carotid if the neck isn't too thick.  The Model 840 operates at a nominal 8 MHz which means the crystals and ultrasonic beam are relatively small so that the artery and vein flow signals are easily separated in the limbs and groin.  A lower frequency Doppler will give better depth but doesn't work as well on the small vessels.

I know there are prettier pocket dopplers around.  But you will not find one that works as well as this or our Model 841-A. I check them personally on my posterior tibial going from the back side of the calf.  They have to give me a good flow signal at that depth or they don't go out the door.  I've tried competitive dopplers that could barely detect the flow under the same conditions -- brand names.

We have ALWAYS made the most sensitive dopplers since the beginning in 1965.  No doppler user with much experience with different makes disputes that.  This is an 8 MHz doppler which does well on toes too.  Feel free to compare a Parks Doppler with any other on the deeper vessels and on the fingers and toes.  That's what counts.  Compare price and performance.  Available for trial.

Loren Parks

This Doppler is successor to our Model 841, our most popular pocket Doppler.  This updated version allows plug-in probes so you can use different probes or just for convenience of replacing defective probes.

Three probe styles are available for the Model 841-A.  The infant flat probe and adult flat probe are used for systolic blood pressure measurements in limbs, primarily at the wrist.  The pencil probe is used for arterial and venous flow evaluation.  Probes for the Model 841-A are made specifically for best performance on the Model 841-A, therefore you should only order probes made for this instrument.  The price is the same.  Compare our replacement probe price with that of other makes. 

Model 842 Pocket Doppler Features: Built-in signal processing for displaying recordings Factory set amplitude control Dimensions: height: 3.8 cm width: 7.9 cm depth: 14.6 cm Built-in speaker Approximate 8 MHz frequency Operates on a standard 9-volt alkaline battery Auxiliary headphone output

The Model 842 Pocket Doppler is similar to our Model 841-A, our most popular Pocket Doppler.  This version does not allow plug-in probes so you must choose a permanent probe type.

The Model 842 Pocket Doppler has a built-in signal processing circuit for displaying blood flow waveforms on an electrocardiograph or research recorder with a DC input and an input impedance of 100 thousand ohms or more.  A 50 millivolt per centimeter deflection factor is optimal.

Three probe styles are available for the Model 842.  The infant flat probe and adult flat probe are used for systolic blood-pressure measurements in limbs, primarily at the wrist.  The pencil probe is used for arterial and venous flow evaluation.  Probes for the Model 842 have shorter cables than standard probes.  Since probes are wired in, US users are often best served by factory replacement of defective probes on this instrument. 

Model 641-A Features: Dimensions: height: 3.8 cm width: 7.9 cm depth: 14.6 cm weight: 12 1/2 oz., 356 grams Built-in speaker Auto-shutoff (5 min) Approximate 2.2 MHz frequency Operates on a standard 9-volt alkaline battery Auxiliary headphone output

This Doppler is the successor to our Model 641.  The battery drain is about half that of the Model 641.  It has a built in timer switch that automatically shuts off the power after about 5 minutes.  The timer protects the battery when the instrument is inadvertently left on.

A clip on the back of the instrument lets you carry it on your belt , and it is small enough to carry in your pocket.  Available with CE mark for Europe.

Our Model 641-A approaches the sensitivity of the bigger units.  However, a smaller Doppler is always a compromise when compared to a larger, more sensitive unit.  Nevertheless, they work very well near term.  Its portability has made it very popular and its sensitivity is adequate for nearly all needs.  At ten weeks I would prefer our Model 611 series.