Adjustable BOOMA Rein: Fits any horse and riding style up to 36 inches Aggressive Riding: Snap BOOMA directly to regular reins Recreational Riding: Attach BOOMA using included easy-to-attach carabiner O-ring The Booma Rein, featuring a Carabiner, is the most favored style for swift and simple application. Ideal for trail rides, lessons, and therapy sessions. This rein also doubles as a performance rein by detaching the Carabiner and directly connecting the Booma Rein to the riding rein. The BOOMA 'rein' is crafted from a robust, waterproof, and flexible premium polypropylene material. The BOOMA Rein is fully adjustable, up to 36 inches, to accommodate any horse and riding style. For more intense riding, snap BOOMA directly onto your regular reins. For leisurely rides, attach BOOMA to your reins using the included easy-to-attach polished steel carabiner O-ring.