A damper device includes a damper main body, and a grommet fixed to a fixing member. A plurality of elongate prisms are located adjacent the light output side of the light guide body. The first and second levers are located on opposite sides of the weapon. The peripheral-side connector also comprises a plurality of mating contacts which are duplicated adjacent to the contacts but in a reverse order. A coefficient of viscosity of the superfluid is virtually zero, therefore friction between the superfluid and the nanotubes is extremely small. The display device includes display means 1, control means 3 that causes the display means 1 to display predetermined display information and updates the display information at a predetermined display update cycle, illumination means 2 that illuminates the display means 1, and dimming means 4 that changes brightness of the illumination means 2.