PentaSense: scanning with one, three or five sensors
The OKM eXp 5500's Super Sensor can be used on its own or with Enhancer sensor modules that plug into its sockets. OKM describes three set-ups:
1 sensor: the Super Sensor alone, for narrow areas such as caves, passages and crevices.
3 sensors: the Super Sensor with two Enhancers on one side.
5 sensors: the Super Sensor with all four Enhancers, the full PentaSense system, which OKM says scans as if you carried five Super Sensors side by side.
The PentaSense Rod holds the probe out in front of you so you can balance it on sloping ground, and OKM says the extra distance between you and the probe keeps you from influencing the measurement. More sensors cover a wide field in fewer passes. OKM pitches the eXp 5500 for rocky mountain terrain and wide desert areas. On a small, cluttered site, the single-sensor set-up is often the easier one to walk.
Three operating modes on the OKM eXp 5500
3D Ground Scan records the scan field for a 3D image in Visualizer 3D Studio Professional Edition on the included Windows notebook. Magnetometer responds to ferrous metal. VLF Metal Detection uses the PentaCoil, a 14 x 10 inch VLF search coil. OKM says the VLF mode offers multi-frequency operation and target ID zones, with preset and custom profiles, adjustable sensitivity for mineralized soil or scrap, and discrimination of gold and silver from iron and bronze relics. That makes the eXp 5500 the OKM in our range for someone who wants multi-sensor survey imaging and a working VLF detector on the same site.
The control unit has an 8.4-inch touchscreen (1024 x 768) that OKM says is easier to read in direct sunlight, and a replaceable lithium-ion battery that OKM rates at about 7 hours at medium brightness and 25 °C, recharged in about 3 hours. The control unit weighs about 1.7 kg.
What comes in the OKM eXp 5500 Professional package
As of October 2026, OKM lists the control unit, Super Sensor with LED Orbit, VLF PentaCoil, PentaSense Rod, telescopic rod, the Enhancer modules, protective caps, carrying strap and backstrap, Bluetooth headphones, pre-configured Windows notebook, USB drive with Visualizer 3D Studio Professional Edition, USB-C charger, Power Pack PP20V3A01 and a waterproof, shock-resistant protector case. The Professional Edition software adds PDF reports, CSV export, scan field overlays and extra soil types over the Standard Edition. OKM notes that delivery contents can vary. You can see the full listing on the OKM eXp 5500 Professional page.
How deep OKM rates the eXp 5500
OKM states that customers have found objects down to 25 m (82 ft) with the eXp 5500 in 3D Ground Scan. OKM gives no test conditions for that figure, and it applies to large objects and voids, not to small metal. The VLF mode is for shallow targets. Ground, target size and how carefully the field is scanned all decide what you see. Our guide How Deep Do Metal Detectors Go? explains why.
Weather and accessories
The OKM eXp 5500 is a dry-weather instrument. OKM rates the control unit, Super Sensor, Enhancers and PentaCoil IP40 and lists them as not waterproof, with an operating range of minus 10 to 50 °C (14 to 122 °F). Move it between sites in the protector case. The sensors and PentaCoil are OKM's own; coils made for other detectors do not fit. OKM sells extra software activations and 3D software training separately for teams that share scan analysis.
What you give up with a smaller OKM
The eXp 5500 sits in a high price band, so it is worth checking which of its features you would actually use. Each smaller OKM gives up something specific.
Drop the multi-sensor coverage, keep VLF and 3D: the OKM Evolution NTX combines a VLF search coil with 3D scanning at a lower price band, without the PentaSense multi-sensor system.
Drop VLF, keep a field screen: the OKM Rover series is lighter for small sites, and the Rover C4 adds Pinpointer and Mineral Scan with its Super Sensor.
Drop almost everything but 3D Ground Scan: the OKM Fusion series is the lowest-cost way to learn OKM 3D scanning.
Drop metal detection altogether: if your targets are non-metallic, such as concrete, pipes, cavities or groundwater, the OKM Gepard GPR uses ground penetrating radar for that. Imaging systems from other makers are in our 3D imaging metal detectors.
