each of the racks 21 a motor 23 securely connected with the gear set 22 for controlling the movement of the racks 21 a pair of bases 25 18 respectively supporting the racks 21 and the gear set 22 thereon and an l shaped link 24 pivotally connected between the underside of the case 43 and the inner face of the body 10 furthermore referring to fig5 a container 50 for storing a fragrant substance not shown is provided in the recess 13 of the body 10 the container 50 has a cylindrical body 51 provided with a closed end 512 an open end 513 with outer threads 511 a cover 52 securely located on top of the cylindrical body 51 to close the open end 513 and having two sets of holes 521 defined in opposite sides thereof and a split bushing 522 formed thereon and having a flange 523 provided on the top edge thereof an outer cover 53 threadingly connected with the outer threads 511 to enclose the cover 52 and having two arcuate slots 531 defined to respectively and selectively corresponding to each set of the holes 521 and a central hole 532 defined to correspond to the split bushing 522 so as to allow the split bushing 522 to extend therefrom and a button 54 having two opposed openings.