referring initially to fig1 and 2 , there is shown a container holder assembly 10 embodying the present invention which includes an integrally molded tray - like base 12 , a top cover 14 and a partitioning arm 16 pivotally mounted to selectively extend within the central storage cavity 15 of the tray 12 for dividing the storage area into one or more areas for holding different sized containers or other objects . the container holder assembly 10 can be mounted to a drawer 18 which extends either from the instrument panel , center console or center armrest of a vehicle in a conventional manner . alternatively , the container holder 10 can be fixedly mounted to such a vehicle accessory and selectively covered or uncovered . the pivoting partitioning arm 16 is shown in a stored position in fig1 in which a projection 17 extends generally centrally within the storage area 15 dividing it into two equal left and right container holder sections , which are further defined by quarter round projection 13 and 19 formed in the tray 12 . when pivoted to an extended position , as shown in fig2 the partitioning arm 16 can selectively close the storage area 15 into a size for containing , for example , a single large mug 20 as opposed to two conventionally sized styrofoam coffee cups or beverage cans , as shown in fig1 . in the stored position as shown in fig1 also the central area 15 of the tray can be utilized for storage of items other than beverage containers . the detailed construction of the tray and partitioning arm are best seen in fig3 and 4 now described . referring initially to fig3 there is shown a tray 12 which can be integrally molded of a polymeric material such as polypropylene and which defines the relatively deep central storage area 15 . the tray includes a floor 11 surrounded by a vertically extending sidewall 21 . extending through sidewall section 21 &# 39 ; of tray 12 is a recess 22 for receiving the pivoted dividing partitioning arm 16 . in the floor 23 of the integrally formed recess 22 is a circular mounting boss 24 for receiving a lower pivot axle 44 of pivot arm 16 which includes an upper pivot axle 46 which extends into a similarly shaped mounting boss aligned on cover 14 . cover 14 includes apertures which align with four corner mounting posts 26 extending upwardly from the top surface 25 of tray 12 for coupling the top 14 to the tray with suitable fasteners 26 &# 39 ; extending upwardly through the mounting posts 26 and self - threading into cover 14 . the sidewall 28 of cavity 22 communicating with cavity 15 of tray 12 includes a plurality of vertically extending semicylindrical detents 29 for selectively holding the partitioning arm 16 in either a stored position , as shown in fig1 or a number of different selectable use positions as shown in fig2 and 4 . for such purpose , the partitioning arm 16 includes a central body 40 having a sidewall 42 to which a detent spring clip 50 is mounted by means of a pair of apertures 52 and suitable fastening screws 54 ( fig3 and 4 ). spring clip 50 includes an outwardly extending arm 56 having a vertically extending semicylindrical projection 58 which nestably fits within the detents 29 as illustrated in fig4 for releasably holding the partitioning arm 16 in a desired position . the end 41 of arm 16 is arcuately curved and fits within a cavity 27 integrally located within cavity 22 through sidewall section 21 &# 39 ; of tray 12 . arm 16 also includes a projection 17 extending into cavity 15 , as seen in the figures , a distance sufficient to be readily accessible and operate not only as a divider as seen in fig1 but also as a handle which can be gripped by the user to move arm 16 from the stored position in which spring clip tip 58 is located within detent 29 &# 39 ; and any of the selected use positions represented by the three - spaced detents 29 in sidewall 28 of cavity 22 . with such construction , therefore , the size of cavity 15 of tray 12 can be selectively changed and employed for storing a variety of different articles including different sized beverage containers including mugs , cans , styrofoam cups and the like . the utilization of a detentable , selectably adjustable arm allows the user to select the desired configuration for a given application . it will become apparent to those skilled in the art that various modifications to the preferred embodiments of the invention as described herein can be made without departing from the spirit or scope of the invention as defined by the appended claims .