Abstract: The present invention essentially comprises an upper assembly having a securing receptor with a guide track, a lower assembly having a securing receptor with a guide track, a bi-fold partition having a top portion and a bottom portion wherein the top portion is received by the upper assembly and the bottom portion is secured by the lower assembly. In a preferred construction, the bottom portion of the partition further has a cooperatively attached pin or foot bolt that is generally received by the lower assembly. When the partition is secured in such a fashion, the partition forms a compartment often referred to as a tack room. To release the partition, the pin is pulled in upward direction and the partition slid out of the lower and upper assembly wherein the partition can be folded and stored along the sidewall of the trailer and in essence removes the tack room sub-compartmentalization.