Robart Pinchless Low Port Grazing Bit Robart Patent #6449930 A revolutionary idea and bit design to implement it. Instead of training and working a horse on the basis of creating pain and the anticipation of pain, the patented David Robart bit corrects by pressure and eliminating the pain. Truly a clever design. This bit is designed as a low port grazing bit with aluminum engraved cheeks. Overall length of cheek piece is 8 1/2. Designed for horses that tend to over bridle. Manufacturer is not responsible for misuse of product. Size: 5.