Zircon MetalliScanner m40 Handheld Electronic Metal Detector

Brand/make: I'm very glad I spent the extra $10 to get this one instead of the Little Wizard II. Zircon seems to be the industry leader in this sort of technology, and seems to be a brand I can trust and get good support from. Their website is well maintained. It's designed in USA; assembled in Mexico. I think it's a newer design than the Little Wizard II, since it was first released in April 2007, whereas the Little Wizard II product manual is dated November 2002.Purpose: I bought this primarily for finding staples/screws/nails in old wood I want to reuse, but I'm sure I'll find other uses for it too, like finding things I drop, finding studs and nail lines, etc.Size: It's a little bigger than I imagined it, but that's a good thing - my fears of it being delicate or likely to be broken were completely unfounded.Battery: I only just got this, so I can't comment on battery life, but it's nice that it came with the 9-volt battery already installed and ready to use.Broad/pinpoint usage: You can use this lying flat for doing a broad sweep, then turn it up and point it like a gun to pinpoint the exact area. That's really handy.Proper usage: This is a sensitive, quality device. Like the directions say, if you move it around quickly changing its orientation, it will give you a false positive briefly, but used properly, it'll work great - just use a steady hand and don't twist it around quickly.Lights/indicators: The scanner has a green "READY" LED under a four red LED "bargraph". This is duplicated on the other side, so you can conveniently see it regardless of orientation. Furthermore, when you're closer than 4 lights, the blue senor lights up and buzzer sounds (engineered at just the right volume, IMO, to be audible but not annoying).Calibration: Rather than fool with a little adjustment screw till you get it to stop whining (like I saw in a video for the Little Wizard II), this is auto-calibrating. Just hold it out away from any metal while you turn it on, and it calibrates based on its surroundings. This is also helpful when narrowing down a piece of metal in an area with other smaller pieces. Just let off of the trigger and turn it back on where it is, and it'll be better calibrated to pinpoint the large piece (strongest influence).Metals: This detects ferrous and non-ferrous metals, though it is more sensitive to ferrous metals. I'm not sure how it works, but there may be a different mechanism involved. For example, with ferrous materials, the scanner seems most senstitive when the object is inline with the sensor rather than turned perpendicularly, whereas overall proximity seems to be the most important factor in detecting non-ferrous metals, regardless of orientation.Large object detection (pinpoint orientation, high calibration):Item: [distance at first light], [distance at buzzer]5-qt stainless mixing bowl: 5.5", 3.5"heavy lineman's pliers: 5.5", 3"3/8" OD copper tubing: ~2", ~3/4" (similar for 5/8" OD copper pipe)14-AWG 2-conductor Romex: ~1", ~3/8"0.024" thick aluminum plate: 4.5", 1.5"(Your mileage may vary...)Small object detection: This found one leg of a common office staple (~6mm long - pretty small!!) in a piece of wood. Properly oriented, it's enough to sound the buzzer. Oriented non-optimally, it may only light up 2-3 lights, but I'm still convinced it would find it buried even an 1/8" in both broad or pinpoint orientation, if you're doing a properly careful search. For non-ferrous metal, I got similar results with a 14mm piece of solid telephone wire.Sensor geometry: The sensor is not as symmetric as it appears. I used the two tiny bits of metal mentioned above to "map" it. The intended pinpoint end is sensitive, whereas the other end isn't very. In the middle zone, there's a variation of sensitivity depending on the material. For ferrous metals, it seemed more sensitive in the very middle, whereas non-ferrous materials were better detected in either direction away from the very middle.Magnetized materials: The usage sheet states: "Magnetized materials may cause false, unstable indications." After experimenting with a small disk-shaped fridge magnet, I don't think that will make a big difference. It seemed to detect it somewhat better facing into one of the poles, and a little less coming at it from the side, which is about what I expected.Bottom line: I'm very pleased with my new "toy" and expect it will serve me well for years to come.

This one gets a full 5 stars. I had to find studs in a wall that has drywall over lath and plaster. I tried everything I could find on the market and nothing worked before I finally gave the M40 a try.I tried base model stud finders, high end stud finders, the Walabot DIY Plus, even the FLIR One infrared camera and even my best strongest magnets. Nothing worked. I've been doing residential construction for 30 years. Admittedly, I haven't had to deal with too many situations like this where there was drywall over lath and plaster, but I have tons of experience looking for structure behind walls. And I thought I would have no trouble with this situation. BUT, I got stumped by it and wasted a lot of time that I could have saved had I known about the M40. It's just plain awesome. It makes you feel like you are in the 21st century, whereas every single other device I used in this type of situation made me feel like I was in prehistoric times, because they just plain old did not work in this situation. I was so frustrated by being stumped that I called a mechanical/electric engineer friend and asked him why stud finders have so much trouble with lath and plaster. I won't go into detail but I now feel like I grasp that engineers really are up against it when it comes to designing a standard (capacitor or radar) stud finder for lath and plaster walls. That made me feel better. I feel like I can sympathize with the designers. But, the M40 gets around the problem. I originally just resorted to drilling to search for the studs in order to install a hand rail. But after the job was done, I tried the M40 on the wall. It took me 10 minutes to find all the studs and I've labeled them with blue tape in the photo. I've now used the M40 on straight lath and plaster walls and on straight drywall. It finds the nails in the lath and finds the drywall screws. I find it more user friendly than any other device I've used. The only drawbacks that I find are...1) that it also finds wires and metal pipes so any time you get a reading you have to go vertical to double check that there is an intermittent screw or nail beep pattern rather than a consistent beep that you get with wires or pipes (but this is a minor issue because it doesn't take long to check)2) you can't really verify center of stud. The device only finds metal, and if the fastener isn't central in the stud, you get the idea.But even with those drawbacks I'm giving it a FULL 5 STARS because it is quick and user friendly.Bravo to the folks at Zircon. All this is not too bash all other stud finders. If there's just straight drywall a lot of them are great, but if there's lath and plaster, honestly I haven't found a single other device that does the job, and I don't think I'm alone in that.

I have been using this for several months and I am able to use it so that it is 100% correct all the time. How you use it and what you are trying to detect makes a difference. I use it to quickly scan the surface of wood for ferrous metals before I put it into a thickness planer. If a thin nail has been driven into a board and I am trying to detect it from the other side (detecting the pointed end of the nail), the Wizard needs to be within 1/2" of the end of the nail. If I am trying to detect a large mass of metal (like an I-beam :) it will detect it from 5+ inches away.It gives many, many false positives (that is, indicates there is metal there when there isn't). The Wizard is constantly adjusting itself to accomodate the substrate the metal might be embedded in, which is always changing since you are moving the Wizard around. However how the device shows false positives is different than how it shows genuine positives (that is, metal that really is there). When I see false positives I move it back and forth over an area that doesn't have metal to let the device "set itself to 0" (i.e., the lights go out). Then slowly going back over the area in question will reveal the truth.I am very happy with this device. I'm only giving it 4 stars because of the useless, too generalized, information given from the manufacturer about the parameters for which it will detect metal.