Bosch CST/berger Magna-Trak MT200 Review: The Magnetic Locator That Finds Buried Survey Pins

In 1962 a survey crew drove out to a boundary line, dug a hole, set a monument in it, photographed themselves standing around it, and went home. That is the entire business model of land surveying: put something permanent in the ground and trust that a stranger, decades later, can find it again.

A 1962 crew setting a boundary monument — permanent, precisely placed, and eventually invisible (photo: Wikimedia Commons).

The trusting part rarely works out. Sixty years of grading, landscaping, fence lines, driveway pours and Arizona caliche later, that iron pin is six inches down under a mesquite and there is no flag on it. Which is why the single most useful tool on a survey truck is not the total station. It is a four-foot wand that beeps at iron.

What a magnetic locator actually does

This is the part people get wrong, so it is worth being blunt about it. A magnetic locator is not a metal detector. It does not transmit a signal and listen for a return. It passively reads distortions in the earth's magnetic field, which means it responds to ferrous objects only — iron and steel. Rebar, iron property pins, steel valve and curb boxes, well casings, manhole covers, cast iron pipe, buried steel tanks, the steel lift handles on a septic lid.

It will not find copper, brass, aluminium, or a PVC water line, because there is nothing magnetic there to distort. It is also not a substitute for calling 811 before you dig. What it is very good at is the job a metal detector is bad at: ignoring the soda can at two inches and screaming about the steel pin at four feet.

The MT200, in numbers

We have one on the shelf: the Bosch CST/berger MT200 Magna-Trak 200 Series magnetic locator with soft case, $495.99. It is the 200 Series unit — the one with the digital readout, not the entry-level 100 Series that only beeps. We identified it from the locator's own rating plate, photographed in the listing:

• Model: MT200 (Magna-Trak 200 Series), catalog no. 19-200SC
• Serial: 622100091  ·  Maker: Robert Bosch Tool Corp., Mount Prospect, IL — assembled in Malaysia
• Display: digital LCD readout with bar graph, plus an audio tone for pinpointing
• Controls: sensitivity and volume both adjustable with the hand that is already holding it
• Erase function: blocks out a nearby magnetic disturbance — a fence line, a parked truck — so it stops masking your target
• Depth: manufacturer states roughly 6 inches to 15 feet, depending on target size
• Power: 6 x AA, with a segmented battery indicator and up to about 100 hours of runtime
• Size: about 42.75 in long, about 4 lb 12 oz

The one-handed design is not a marketing line. The whole point is that your other hand is holding a probe, a shovel or a can of marking paint, because the moment the tone peaks you want to mark the spot before you move your feet.

The condition, stated plainly

This unit is open box, and we would rather lose the sale than oversell it. The locator and its black CST/berger soft case are both present and both photographed. Our warehouse intake photo shows it powered on with a full battery indicator — that is the extent of what has been confirmed. We have not field-tested it, depth-tested it or calibrated it, and we make no calibration claim. Battery condition and any paperwork are unverified. No damage is visible to us. Verify it on a known target before you rely on it for professional work.

What else you want in the truck

Finding the lid is step one. Getting it open is step two, and a screwdriver in a manhole slot is how people wreck their backs — we have an Olympia Tools 30 in manhole cover hook for storm drain and septic lids, $65.99 for exactly that. If the target is in a lane or a drive, the 48-inch roll-up ONE LANE ROAD AHEAD MUTCD construction sign, $118.99 and a set of Pangda reflective bollard post sleeves, 4-pack, $164.99 keep traffic off you while you dig. For marking out a grid on pavement or a warehouse floor, there is a 16-roll case of ProTapes Pro 50 vinyl safety marking tape, 3 in x 36 yd, $201.99. And for reading a monument cap across a wash without walking it, a 12x50 HD monocular with phone adapter and tripod, $119.99 lives in a lot of survey trucks.