The Solinst 122 Interface Meter locates and measures the depth and thickness of oil or other non-aqueous product layers floating on or sitting below water in a well, borehole, or tank. A stainless-steel P8 probe on a graduated, laser-marked flat tape contains an infrared emitter/detector aimed through a Hydex cone tip, plus a stainless-steel conductivity pin. As the probe descends, entering any liquid refracts the IR beam away from the detector, triggering a light and audible tone. If that liquid is non-conductive (oil or other product), the signal stays steady; if it's conductive (water), a separate circuit overrides the IR signal and makes the light and tone intermittent. Reading the tape at each transition point — and subtracting — gives the depth to product, the product/water interface, and the layer thickness.

• Laser-marked flat tape accurate to 1.0 mm or 1/200 ft
• Single 9V battery with roughly 120 hours of operating life and automatic shutoff
• Grounding cable, cleaning brush, and tape guide included
• CSA-based approval for Class I, Division 1, Groups C&D hazardous locations
• Available in tape lengths from 100 ft to 1250 ft

Typical uses include detecting LNAPL (floating product like gasoline or oil) and DNAPL (sinking dense product) layers in groundwater monitoring wells, petroleum storage tank monitoring, and contaminated-site investigation.

Replacement parts and accessories are available in the Solinst 122 Interface Meter Parts & Accessories collection.