TES10B Digital Tesla Meter Gaussmeter with 0-200mT/0-2000mT Range Auto-Switch | 0~100mT Accuracy ±1%/ 100~2000mT Accuracy ±2% Gauss Meter for DC Magnetic Field Testing | Includes NS Function & Probe

Had to learn the correct way to use it. With the numbers on the probe facing you, and the other side against the magnet it reads the proper polarity. Great tool to determine polarity and strength of various magnets and electromagnets.

Not so very long ago, reasonably priced test equipment was as rare as a free parking space in Brooklyn. But, with the influx of massive amounts of Sino-produced goods via Amazon, an entire array of useful and even highly specialized gadgets have entered the U.S. market.The AMTAST TES10B is a handheld battery powered dual range teslameter that is capable of detecting fairly small magnetic fields, as well as indicating magnetic polarity of that field. With this meter, one can conduct an entire series of investigative efforts in the practical magnetics and electronics with a reasonable degree of accuracy, given the price point of this meter.The device features two display range units, the Tesla and the Gauss, which are different though related kinds of magnetic readings. The actual measurements are taken via a small hand-held probe which is small enough to fit into a variety of spaces where magnetic measurements might be needed. The probe is equipped with a protective removable cover, which is a good thing, since the probe itself is quite slender and is made of circuit board material. It would be quite easy to crush, break, or destroy this little probe, so the user is wise to take precautions as to how, where, and how roughly they utilize the probe tip when getting measurements.The unit comes with a handy wal-wart, which saves on batteries if one is using the device in a bench-only mode. It also operates on four AA sized batteries, which in my unit were included - though the seller informs buyers that "batteries are not included". Not sure, but mine had them. Anyway, the unit operation is quite straightforward, and the manual includes enough information to get you on the road to measuring magnetic fields with reasonable accuracy. The display is large and easy to read, and the various modes are obvious and responsive to push-button commands. The display has a backlight feature that is selectable, and the two SI (tesla and gauss) units are selectable via their own dedicated pushbotton as well.The case is made of the usual and popular hard plastic that dominates instruments of this class, and is completely conventional in design. It is reasonably robust, though one would excercise reasonable care in handling. It is not something to toss in the bottom of your toolbox, especially not the probe, which has a protective cover that should always be kept in place when not measuring, or YOU WILL BREAK THE PROBE! you have been warned. :-)The entire system comes in a nicely put togther blow mold plastic case which I particularly appreciate as it has specific cut foam locations for each tool part, as well as actual pin-hinged latches, as opposed to those one-piece molded snaps that always seem to break off after a few years.The weakest point in the entire device is one that is actually good for a few laughs. I'm speaking of the "instruction manual". This manual is obviously translated from Chinese to English (sort of) by a machine, and then not proofread by anyone native or trained in the English language.As a consequence, it contains dozens of linguistic howlers that make for great fun reading. Ultimately, it does get the job done of explaining the unit, though not without a few head scratching moments - most of which are sure to bring a smile to any native English speaking person's face.Overall, I rate this device five stars - for what it is. A practical low-cost and reasonably accurate hand-held teslameter that can provide lots of quick answers to anyone working with magnetic fields and magnetic devices where polarity matters.Recommended for guitar technicians who need to confirm pickup polarity as well as magnetic strength. Also good for those building anything with magnetic sensors, as well as those working on devices where stray or excessive magnetic fields can damage or cause operational malfunction. Data centers, tape storage locations, electronic technicians working with transformers and electrical systems subject to high amounts of stray magnetism. All these types and more can benefit from this handy and easy to use tool.FIVE STARSPros: Reasonably priced, easy to understand and operate, portable but also bench powerable, large easy to read display, rapid power-on cycle, nice protective case.Cons: probe is small and fragile - exercise caution when using. Range of sensitivity is fixed - and while useful for that range, the inability to auto-range, or manually jump ranges means that very low stray fields might be missed, while very large and strong fields will overwhelm the device's ability to give a useful reading.