The Elcometer 211 Magnetic Coating Thickness Gauge (part numbers A211F-1M and A211F-8M), widely known as the "Banana" or Inspection Gauge, is a mechanical pull-off gauge that measures the dry film thickness of non-magnetic coatings over steel. It solves a specific problem: measuring coating thickness where electronic instruments cannot safely or practically be used, such as inflammable atmospheres in oil and gas production and underwater dry film inspection. With no battery or electronics, it works reliably on cold surfaces and in conditions that would defeat a digital gauge.

The Elcometer 211 Magnetic Coating Thickness Gauge uses a permanent magnet balanced against a calibrated spring. As the gauge is rotated, the magnet lifts off the coated surface at a point set by the coating thickness, which is read directly from the scale. It is factory calibrated, with user calibration adjustment, and supplied with foils to check calibration on site. Accuracy is plus or minus 5 percent of the reading or plus or minus 2.5 micrometres, whichever is greater. The metric version (A211F-1M) reads 0 to 1000 micrometres and the imperial-range version (A211F-8M) reads 0.65 to 6mm. A V-grooved base seats it on curved work, which suits pipeline inspection. Substrate thickness must be at least 0.4mm and readings kept at least 6mm from an edge.

The Elcometer 211 can be used in accordance with ISO 2178, ISO 2808, ASTM B 499, SSPC-PA2 and others. Used in coatings inspection, marine and pipeline work, it is supplied by BAMR, South Africa's authorised Elcometer distributor.