Nokta INV56 22" x 19" Waterproof DD Search Coil for Invenio Detector

The Nokta INV56 coil is compatible exclusively with the Nokta Invenio metal detector. This 22x19 DD coil was engineered specifically for the Invenio's multi-frequency architecture and 3D imaging system, and it will not physically or electronically connect to other Nokta detector models like the Simplex, Legend, or Anfibio. If you own a Nokta Invenio, this coil integrates seamlessly with your detector's existing settings and 3D imaging modes. For compatibility questions about other Nokta Invenio accessories, contact our team before ordering.

The INV56 measures 22 inches by 19 inches in an elliptical shape, providing substantial ground coverage. This size translates to wider ground coverage per sweep, allowing you to clear large fields, beaches, or survey grids in fewer passes. The tradeoff is reduced maneuverability in tight spaces like dense brush or confined building foundations. The larger footprint also increases depth on bigger targets such as caches, large relics, and deeply buried coins, though small targets at shallow depth may be easier to pinpoint with a smaller coil. The 22x19 elliptical design covers more ground with each sweep compared to typical detector coils.

The INV56 is fully waterproof and submersible, making it suitable for surf zone detecting, shallow river hunts, and wet-sand beach work. The DD coil configuration provides effective ground balancing in saltwater environments where high mineralization can destabilize other coil types. You can run this coil in the surf and across tidal flats without risking water damage. For saltwater beach detecting, pair the INV56 with your Invenio's beach mode to handle the conductivity of wet sand and seawater while maintaining stable target signals on coins, jewelry, and relics buried in storm cuts.

The DD (Double-D) configuration on the INV56 coil delivers superior ground balancing in mineralized soil, wet sand, and saltwater environments compared to concentric coil designs. DD coils transmit and receive signals in overlapping D-shaped patterns, which reduces ground interference and maintains target separation even when soil conditions are challenging. This makes the INV56 effective in iron-rich ground, black sand beaches, and areas with high salt content. The DD design also provides better depth on larger targets and maintains signal clarity at the edges of the coil's detection field, which is critical when you're covering ground quickly with a 22x19 footprint.

The INV56 increases detection depth primarily on larger targets like caches, large relics, deep coins, and sizable metal objects due to its 22x19 coil diameter. Larger coils generate a bigger electromagnetic field, which penetrates deeper into the ground and detects bigger targets at greater distances. However, small targets like individual coins or small jewelry at shallow to moderate depth may not see a dramatic depth gain, and the larger coil can make pinpointing small targets more difficult compared to a smaller coil. If your primary goal is maximum depth on large targets in open ground, the INV56 delivers. For tight-space hunting or small-target pinpointing, a smaller coil remains the better tool.

The live product data does not specify the exact weight of the INV56 coil, but any 22x19 elliptical coil will add noticeable weight and leverage to your detector setup compared to the stock Invenio coil. The larger surface area and longer swing radius increase arm and shoulder strain during extended detecting sessions. Detectorists working large sites with this coil often take more frequent breaks or use a harness system to distribute the weight. If you plan multi-hour hunts with the INV56, consider a detector harness or chest-mount rig to reduce fatigue. For information on weight-distribution accessories, explore our full coil selection and contact our team for setup advice.

The INV56 can handle trashy sites due to its DD configuration, which maintains target separation better than concentric coils in iron-contaminated ground. However, the 22x19 coil size makes it less maneuverable in tight spaces and more likely to detect multiple targets simultaneously in dense trash fields. If you're working a park with heavy aluminum and iron debris, a smaller coil will give you better target isolation and easier pinpointing. The INV56 is better suited to open ground with scattered targets where its coverage advantage outweighs the need for tight target separation. For trashy urban sites, stick with a smaller coil and switch to the INV56 when you move to open fields or beaches.

The INV56 coil is designed specifically for the Nokta Invenio metal detector. The compatibility specifications state this coil works with the Nokta Invenio metal detector only. If you own an Invenio and need wider ground coverage for large-site surveys or beach detecting, the INV56 provides excellent depth and coverage benefits with its 22x19 elliptical DD configuration. The fully waterproof construction makes it versatile for all detecting environments from dry land relic hunting to surf and shallow water treasure hunting. For questions about compatibility with specific Invenio models or settings, contact our team for detector-specific guidance before ordering.

A 22x19 coil requires a slower, more deliberate swing than smaller coils to maintain consistent ground coverage and avoid missing targets at the edges of the detection field. Keep the coil level and parallel to the ground throughout the sweep, and overlap each pass adequately to ensure no gaps in coverage. The larger footprint means you cover more ground per swing, but swinging too fast can cause the coil to lift at the ends of the arc, reducing depth and target detection. Practice your swing in an open area before heading to the field, and adjust your pace until you can maintain a smooth, level sweep without excessive arm fatigue.

DD coil technology uses overlapping D-shaped transmit and receive windings to reduce ground interference and improve target separation in mineralized soil, which is why the INV56 performs well in challenging ground conditions. To understand how DD coils compare to concentric and monoloop designs, and when each coil type excels, visit our metal detector technologies page. That resource explains the physics behind coil configurations, frequency selection, and ground balancing, helping you choose the right coil for your hunting environment and target types.