These pair of highly transparent water baths are for detecting undesirable foaming characteristics in lubricating oils, which could cause inadequate lubrication, overflow and cavitation.

The instrument comprises a high temperature (normally 93.5 °C) and a low temperature (normally 24 °C) bath, each with the capacity to hold four 1000 ml graduated glass cylinders.

Each bath assembly comprises an inner glass bath contained in a polycarbonate safety vessel, a top mounted thermostir unit.