For measuring the grease level in a holding tank. Comprises two 1.22m (4ft) transparent plastic tube sections that screw together and are 3.5cm in diameter to allow small food particles to pass easily through the valve opening at one end. The sections are marked at 0.3m (1ft) intervals. The valve automatically opens when immersed and closes when the sample is removed. It can be re-opened by touching the top valve on a hard surface. Note: not suitable for solid or semi-solid materials.