Panasonic sleeve fiber is ultra-small diameter fibers with a compact head ensure precision centering accuracy to stably detect minute parts. It is suitable for sensing in narrow locations and sensing minute objects because the fiber tip is a thin sleeve. The 40 mm 1.575 in sleeve type can be bent in any direction. Ultra-small diameter fiber with ø0.125 mm ø0.005 in beam axis is able to detect the insertion or bending of fine-pitch connector pins. Fiber can be installed with only the ø0.25 mm ø0.010 in sleeve close to the minute section. It has toughness that can be used in moving parts, toughness that can be bent with precision,and high-quality for all purposes. It changes common knowledge about fibers.