the illustration in the drawing is schematic . it is noted that in different figures , similar or identical elements are provided with the same reference signs or with reference signs , which are different from the respective reference signs only with a first digit . referring to fig1 - 3 , a hairbrush device 100 according to an exemplary embodiment of the invention is illustrated . the hairbrush device 100 comprises a handle 102 , an actuation element 104 in the form of a rotating wheel , a tubular base body 106 , and six filament carriers 108 a - f . each of the filament carriers 108 a - f comprises a rectangular cuboid shaped body 310 a - f having an extension of about 100 millimeters ( mm ), a thickness of about 2 mm to about 5 mm and a height of 10 mm ( fig3 ). a first plurality of brush filaments 112 are arranged in a row 313 a - f on a first longitudinal side 314 a - f of the filament carrier 108 a - f having the smaller width , and a second plurality of brush filaments 116 is arranged in a row 315 a - f at the longitudinal side 318 a - f of the filament carrier 108 a - f which is opposing to the longitudinal side 314 a - f . each of the first plurality of brush filaments 112 is made from horse hair and has a length of 12 mm and a diameter of 0 . 1 mm , and each of the second plurality of brush filaments 116 is made of a nylon material and has a length of 7 mm and a diameter of 0 . 3 mm . the first plurality of brush filaments 112 comprises a blue color , and the second plurality of brush filaments 116 comprises a black color . for illustration purposes , reference numerals are only assigned in fig3 in association with the filament carrier 108 b . the tubular base body 106 comprises a plurality of apertures 120 which extend vertically to a longitudinal axis 122 of the tubular base body 106 of the hairbrush device 100 . each of the plurality of apertures 120 is designed as an elongated hole through which the first or second plurality of brush filaments 112 , 116 extend . the actuation element 104 is two - directionally rotatable around the longitudinal axis 122 which is identical to a longitudinal axis of the actuation element 104 . each of the filament carriers 108 a - f is mounted to the handle 102 via bearing pins 324 a - f in a two - directional rotationally movable way and is rotationally movable around its longitudinal axis 325 a - f ( fig3 ). each of the longitudinal axes 325 a - f runs parallel to the longitudinal axis 122 of the hairbrush device 100 . each of the filament carriers 108 a - f is welded to a respective gearwheel 326 a - f having an inner opening 328 a - f through which the bearing pin 324 a - f extends to be connected to the handle 102 . further , the gearwheels 326 a - f comprise external toothings 330 a - f formed on outer surfaces of the gearwheels 326 a - f . the actuation element 104 comprises an internal toothing 332 which is formed on an inner surface of the actuation element 104 and which engages with the external toothings 330 a - f of the gearwheels 326 a - f . further , the hairbrush device 100 comprises a locking mechanism 334 formed by a fixing element in the form of a spring - loaded ball rotationally fixed to the handle 102 and respective first and second recesses 336 a , b formed at a front surface of the actuation element 104 facing to the handle 102 . the first and second recesses 336 a , b are arranged at diametrical opposing positions along a circumference of the actuation element 104 . in operation of the hairbrush device 100 , a user of the hairbrush device 100 actuates the actuation element 104 by rotating the actuation element 104 around the longitudinal axis 122 of the hairbrush device 100 along an arrow 138 . accordingly , the internal toothing 332 of the actuation element 104 and the external toothings 330 a - f of the gearwheels 326 a - f roll relative to one another such that the gearwheels 326 a - f rotates along their rotational axes 325 a - f . since the gearwheels 326 a - f are attached to the filament carriers 108 a - f , the filament carriers 108 a - f are rotated along its respective rotational axis 325 a - f along an arrow 340 a - f until the fixing element connected to the handle 102 engages with one of the first and second recesses 336 a , b formed in the actuation element 104 . when the fixing element is in engagement with the respective one of the first or second plurality of recesses 336 a , b , either the first plurality of brush filaments 112 or the second plurality of brush filaments 116 extend through the plurality of apertures 120 formed in the tubular base body 106 . fig1 shows the hairbrush device 100 in a first position 144 , in which the first plurality of brush filaments 112 extends through the plurality of apertures 120 of the tubular base body 106 and is thus selected for a use . in the first position 144 of the hairbrush device 100 , the filament carriers 108 a - f are rotated by angles of 0 degree (°), 60 °, 120 °, 180 °, 240 °, 300 °, and 360 ° equaling to 0 ° measured with respect to a common coordination system . fig2 shows a second position 246 of the hairbrush device 100 , in which the second plurality of brush filaments 116 extends through the plurality of apertures 120 of the tubular base body 106 and is thus selected for the use . in the second position 246 of the hairbrush device 100 , the filament carriers 108 a - f are rotated by angles of 180 °, 240 °, 300 °, 360 ° equaling to 0 °, 420 ° equaling to 60 °, 480 ° equaling to 120 °, and 540 ° equaling to 180 ° measured with respect the common coordination system . while the invention has been illustrated and described in detail in the drawings and foregoing description , such illustration and description are to be considered illustrative or exemplary and not restrictive ; the invention is not limited to the disclosed embodiments . other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention , from a study of the drawings , the disclosure , and the appended claims . in the claims , the word “ comprising ” does not exclude other elements or steps , and the use of the indefinite article “ a ” or “ an ” does not exclude a plurality . the mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage . any reference signs in the claims should not be construed as limiting the scope .
a hairbrush device comprises a first plurality of brush filaments and a second plurality of brush filaments . a property of the first plurality of brush filaments and a respective property of the second plurality of brush filaments are different from one another . in order to reversibly select a stiffness of the hairbrush device , the hairbrush device comprises an actuation element being in driving connection with the first and second plurality of brush filaments and configured for being actuatable for selecting the first plurality of brush filaments or the second plurality of brush filaments for a use .