Magnetic Locators / Pin Finders

Magnetic Locators, or pin finders, are an important tool in the surveyor’s arsenal. A surveyor needs a tough, reliable, and simple pin finder, which is why Bench-Mark carries both Subsurface Instruments and Schonstedt pin finders. The base models, the ML-1 magnetic locator and the Schonstedt GA-52Cx, are made of aluminium monotube construction and feature two sensors, to more easily locate a pin that lies close to another ferrous object (a fence). Both are backed by seven year manufacturer warranties, and are designed for easy one handed operation. With identical performance, both are excellent surveyor’s instruments, and have proven themselves overseas, serving as mine detectors in Afghanistan. We also carry the ML-1M magnetic locator, which offers the same performance of the ML-1 with the added benefit of an LCD screen giving you a visual read-out of the signal strength and all your instrument parameters. The ML-3 pin finder, available in both 40 inch and 55 inch length models, offers the same outstanding performance with the added benefit of being 100% water-proof, tested to a depth of 220 feet. The short length is very convenient and allows for access to tight spots, while the ML-3 long gives you the ability to make the longest sweeps, without compromising accuracy. Both models of the ML-3 are equipped with LCD screens. Bench-Mark stands behind all magnetic locators we sell, and will beat any Calgary based competitor’s price on the SubSurface ML-1.

Magnetic Locating Best Practices

When using a pin finder to locate survey pins, it is important to remember that a survey marker is typically at least 18” long and located vertically. This means that a survey pin’s magnetic field is larger, and therefore able to be detected from a greater range than objects that may be causing interference. By raising the locator a foot off the ground, you will be able to pick up the survey pin without the background noise of other ferrous objects. When working near a metal fencing, walk at least a foot away, the magnetic field of the fence should drop off sharply, while the magnetic field of the pin will remain strong, enabling you to detect the unique signature of the survey pin.

Once you have a general idea of the location of the marker you are looking for, hold your magnetic locator vertically and criss-cross the location, trying to create an X where the tone of the pin finder is loudest. This will enable you to use your magnetic locator to locate the survey pin accurately.

Subsurface ML1 Magnetic Locator

The Subsurface ML1 magnetic locator is the best value for money when it comes to pin finders. Competitively priced, it offers world class performance in a compact package, just 38.75 inches long. It has a long battery life, 40 hours minimum in the field, and weighs only 2 pounds, including batteries. Designed for one handed operation, you do everything from adjust gain to volume with only 3 buttons, and the micro-processor always remembers your settings.Backed by a 7 year manufacturers warranty, and constructed of high strength aluminium and ABS plastic, you never have to worry about missing a days work. Comes with a soft carrying case, with an optional hard case.

Subsurface ML1M Magnetic Locator

The Subsurface ML-1M pin finder combines all the advantages of the ML1, with the added bonus of an LCD screen giving you a visual readout showing positive or negative polarity and your signal strength. Designed to operate exactly the same as the ML1 pin finder, the ML1m magnetic locator gives you added functionality, without added learning curve.

Subsurface ML3S Magnetic Locator

With the Subsurface ML3S pin finder, never worry about weather again.Waterproof to a depth of 220 feet, the ML3S is constructed of aircraft grade aluminium and comes with both audio and visual outputs. With an overall length of 40 inches, a battery life of over 60 hours, and a weight of 1.8 pounds, this is a pin finder that you won’t have to worry about carrying all day. Backed by the Subsurface 7 year warranty and Benchmarks performance guarantee, this is a pin finder thatr will meet your survey needs.

Subsurface ML3L Magnetic Locator

The ML3L comes with all the features of the ML3S in a 55 inch long package, allowing you to cover more ground and find more pins without compromising accuracy.

Schonstedt GA-52CX Magnetic Locator

The Schonstedt GA-52CX is the original survey pin finder. Constructed of durable aluminium, the GA-52CX is designed for easy one handed operations, with only two switchs to worry about. Comes equipped with hard case and users manual.

(2.1) Subsurface Instruments ML-1 Magnetic Locator

Product Details
  • Easy and simple one-hand operation
  • Volume built into the on/off key
  • Electronic keypad “clicks” when keys are depressed
  • Microprocessor remembers the volume and gain setting
  • Strong aluminum microtube construction provides the best structural integrity
  • Lightweight, only about 2 pounds


Package Includes:
  • Soft Case
  • 4 Alkaline 9-volt Batteries
  • Operators Manual

(2.4) Subsurface Instruments ML-3L Magnetic Locator

Product Details
  • Waterproof up to 75 feet
  • Visual LCD Display
  • Low Battery Indicator
  • Detects Ferrous Objects up to 8 feet deep
  • 55″ long
  • Exceptional Durability
Package Includes:
  • Soft Carry Case
  • 3 Alkaline 9-volt Batteries
  • Operators Manual