Reversing DC motors requires a specific type of switch, namely a DPDT (double pole, double throw) switch (center off) wired in what is known as an 'H Bridge' configuration (pictured at right), so called because the current flow looks like the letter H when you look at a schematic diagram. The 4 upper and lower poles are cross-connected and the motor and power supply are attached as shown in the picture.
Suitable voltage: 5V , 12V , 24V and 48V
Suitable current: 6A