Robart Pinchless Offset Sweet Iron Dee 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. Black sweet iron offset Dee with copper inlay. Designed for starting young horses. Size: Mouth size 5 Inside ring is 3 Thickness of mouth is 11mm.