Multi fit Quick Connect Plates are designed to offer even more flexibility and will fit a much wider selection of king pin boxes by using a design that accommodates all C measurements (length of the king pin box front-to-back). Confirm your trailer's A and B measurements using the measurements below. CAUTION: Measurement cannot be smaller than noted below. * A = 12, 12-1/4 inches, 12-3/4 inches * B= 5-3/16 inches to 6-5/8 inches * C= All Tip: Use straight edge when measuring to the leading edge of pin box.