flat stylus (see picture) are a set of plates of a certain thickness with the appropriate marking, used to measure various gaps. Also, flat feelers can be used, for example, to measure end play where the use of a dial gauge (see below) difficult.
The flat stylus set must be protected from excessive force and impact so that the stylus blades are not bent or damaged. The surface of flat probes must be kept clean and covered with the thinnest layer of oil to prevent corrosion processes.
When measuring the gap, it is necessary to choose a flat feeler gauge that will enter with little resistance between the two parts. It is recommended to have two sets of flat probes to ensure accurate measurements.