This device goes by various names; Vienna Side Reins, Sliding Side Reins and Vienna Lunge Reins. It is used to encourage the horse to learn to balance himself, round his back and carry himself properly on the bit. The action of the reins is similar to that of the German Martingale in that the horse adjusts himself to the pressure of the reins without the rider pulling or a regular side rein that is stationary. It attaches to the girth with a snap or a girth loop, runs up through the bit and hooks to the rings on a surcingle or saddle. Bridle, bit and surcingle not included.