Kant-See-Bak blinds (sometimes referred to as "Dolly Varden" blinds), are perhaps the most widely used type of blinker in harness racing. They are designed to prevent horses from seeing behind, so that they are more inclined to focus on going forward.
This Pony Trot model has a wire "stay" in the top to help keep the blinds in the optimum position in relation to the eye. It also has billet ends for attaching to the bit.
It is available as an option in Pony Trot Harness Sets.