Overfill Prevention Gauge for Above-ground Storage Tanks (AST Gauge)
The standard Overfill Alert Gauge (Type OF), is a pop-up overfill alert gauge with galvanized steel wetted rods,aluminum bushings, and a high-density polyethylene (HDPE) or polypropylene (PP) float (float material determined by the depth of the tank). This gauge is designed to be used on IBC Tote Tanks or Drums with depths from 6" up to 40", and with a 3/4" NPS bung opening. The Overfill Alert Gauge is a high level visual gauge designed to visually alert you that your AST (tank) is near full. This overfill monitor's simple pop up mechanical design promotes easy installs, maximum durability, and low up front costs. Excellent gauge material compatibility for: Diesel, Gasoline, Hydraulic Oil, Transmission Fluid, Isopropyl, and more. Other options are available for increased compatibility with various liquids.

Key benefits:
  • Designed to alert when tank is about 90% full
  • Custom sizes from 6 inches to 40 inches
  • Available in .75" NPS. (1.5" and 2" NPT models also available)
  • Multiple material options and accessories available
  • When ordering specify the exact length needed - every gauge is made custom to fit your tank
  • Length is the point at which you want the level of the tank to read the overfill
Overfill Gauge Overfill Prevention Ordering Instructions
The length of the overfill gauge shall be the distance from the top of your gauge threads to the full mark in your tank. Your full mark should be no less than 90% capacity, and no more than 95% capacity. These measurements will vary depending upon each individual tank. It is the customers responsibility to ensure that we receive the proper measurements for correct overfill warning.


This information has been provided as a general guide. It is the customer's responsibility to select the proper container for product and application compatibility.

Additional Information

More Information
GasketNitrile (Buna-N)
Country of ManufactureUnited States
ModelType OF-0.75
Opening Size3/4" NPS
Rod MaterialGalvanized Steel
Bushings MaterialAluminum
Float MaterialHDPE
CalibrationPlastic Calibration
Note:**Custom configure this product with the options below
**Overfill Depth - Length is the point at which you want the level of the tank to read the overfill.
Q & A
Customer Questions
Can you ship internationally? Where are you located?
The Cary Company online ordering platform is only set up to ship within the United States. For international shipments, please contact us at 630.629.6600 or Sales@thecarycompany.com, and we will be happy to process your order. Our main warehouse and office are located in Addison, Ill. We also have warehouses in across the United States that you can see here. Thank you for choosing The Cary Company.
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