Panasonic FX-301-F7 (Note 1) dedicated for the leak detection fiber FD-F71 and the FX-301-F dedicated for the liquid detection fiber FT-F93 are available. Optimal setting is possible with easy operation. Note: Panasonic FX-301-F can be also used by setting it to leak detection mode. However, the functions are different from the FX-301-F7 dedicated for the leak detection fiber, so it is recommended to use the FX-301-F7 when using the leak detection fiber. Both main and sub units utilize the same amplifier body. This feature allows for easy mounting in the side-by-side configuration. The main and sub unit functions are distinguished only by the proper use of 3-core main cable and the 1-core sub cable. Moreover, by utilizing the same body for both main and sub units, inventory management and maintenance is simplified. Threshold value will be set automatically to -20 % of the incident light intensity during the teaching to steadily detect the leak. It is also possible to change the threshold value to -15 % or -30 %. Entry beam intensity is checked at regular time interval (10 min.), and threshold value is reset automatically.