72 of the paint container 2 to secure the paint container and prevent it from rotating within the mixer receptacle 78 figs illustrate an adapter 10 for securing the first quart paint container 6 or the second quart paint container 8 and for mounting into the mixer receptacle 78 according to one embodiment of the present invention adapter 10 when in a closed position as shown in fig has a shape that approximates a generally right circular cylinder with a pair of lateral projections 12 oppositely positioned from each other that closely approximates that of the gallon paint container 2 adapter 10 is thus sized and shaped to fit securely within the mixer receptacle 78 adapter 10 has a first member 14 and a second member 16 rotatably coupled to each other by a pair of hinges 18 first and second members 14 and 16 are made of an injection molded nylon material although other materials may be used when in the closed position the first member 14 and the second member 16 are releasably secured to each other with a spring clip 20 which is rigidly attached to the first member 14 and releasably secured to the second member 16 as will be described in more detail below outer surfaces 17 and 19 of first and second members 14 and 16 respectively collectively define the outer envelope of the adapter 10 fig shows adapter 10 in an open position and reveals an inner surface 22 of the first member 14 and.