Works greatTD8620 Handheld Digital Tesla Meter High Precision GaussmeterThe Amazon listing stated the product would arrive in approximately 1 week. Then after the order was placed, the delivery date was about 1 month. The product shipped roughly the day after I ordered it, and from China.I received the meter roughly 8 days after the order was placed. So, I am very happy with the quick shipping by the seller!The meter arrived unharmed in a small tan "gift" box. The box is a sturdy single-ply cardboard, but actually nicer than I expected. There is an instruction manual included, and is entertaining to read through. The device is very easy to use, and if you can install the battery, you should be able to operate the meter. Read the manual anyway.There is a protective cover over the Hall Sensor. The cover fits snugly when installed, and must be removed to take readings. Be very careful when removing the cover, as the sensor and the arm it is mounted on could be damaged.The meter case is all plastic, not an expensive looking item, perhaps slightly toy-like in appearance. The simple function buttons are easy to operate, positive in action and well, simple to use. The lead from the meter to the hand-held sensor is reasonably long, long enough to almost get in the way.I don't know if the meter is calibrated to any scientific standard, but it does measure consistently and repeatably.Currently, I use the meter to measure the strength of guitar pickup magnets, and other similar items. I do not know if this meter can measure neodymium magnets, as they may be out of range.For the price, this appears to be exactly what I needed in a gaussmeter.I'm using this for measuring the strength of guitar magnetic pickup magnets. It also shows the magnetic polarity ie: North or South poles. It is very important how you orient the probe in the magnetic field as the maximum field reading is obtained when the field lines are orthogonal to the face of the sensor chip. Making a drawing of how the field lines should be oriented around the magnet being measured can be helpful.This meter is a very inexpensive Hall Effect measurement. It's simple and intuitive to use. The probe contains a Hall effect sensor mounted on a thin pc board, so it is very fragile. I was considering making my own meter before I found this product. I cannot vouch for the absolute accuracy, but then I knew I wasn't buying a lab standard for 30 bucks. I was able to tell the difference between Alnico 2, Alnico 5 humbucker magnets and compare these to Neodymium magnets.The first thing you should know, is that this instrument works very well. Although I didn’t have a standard for comparison, the readings appeared to be correct for the circumstances, and were also consistently repeatable. I also like the fact that the meter could be zeroed between readings. The only negative which was too insignificant to subtract a star, what the somewhat cheap appearance due to what appears to be a vacuum molded case, as opposed to be injection molded. Something to keep in mind, is that you will probably be taking your readings in “mT”, Which is milliteslas. (1/1000) of a Tesla. If you want to know what that is in Gauss, you will need to multiply the reading you see by 10. This is because it takes 10,000 Gauss to equal 1 Tesla. For example, a reading of 3.6 mT = 36 Gauss. Overall, I was very pleased with this product. It also comes with a nice case for transportation, and a decent manual.Such an excellent little tool for precisely quantifying tiny magnetic fields!This Tesla/Gauss meter seems to work well. I've not calibrated it but it does give me important readings that I need for my experiments with magnetic fields. Worth the $100.Very nice once you understand the probe is not identical on both sides, only one side seems to work for measurement. With that said, I measured a magnet (hobby reasons, perhaps even learning something) quite easily. Very nice gaussmeter for the price, thank you.I have needed this instrument for 50 years. Works great. Building guitar pickups? You need one of these.