The back plate of this Restrainer is divided into two separate adjustable pieces, a curved back plate and a rear plate, providing a perfect fit with no gaps. The back height is adjustable from a minimum of 11.4 cm (4-1/2 in) to a maximum of 17.8 cm (7 in) and is secured by tightening 4 knobs. The rear plate has an extra extension plate that can slide up to match the height of the back plate for securely restraining the animal.