The wasting of cutting fluid mists and contamination of a machining environment with cutting fluid mists are prevented by feeding optimum amounts of cutting fluid mists in a variety of machining operations. The memory module may include a memory chip, a controller controlling an operation of the memory chip, an optical detector converting an external input signal into an internal input signal to transmit the converted signal to the controller, and an optical generator converting an internal output signal received from the controller into an external output signal. 25 or 2 inch trailer hitch mount.