Prolite GP Girth in Black. The Prolite GP Girth is a technical girth that has been designed with the horse's comfort and freedom in mind. The technical design of the Prolite Girth can help to improve neatness over the fence, reduce pressure making it more comfortable for the horse and increases power on take off. The Prolite Girth is a perfect option for competition or everyday use. The GP Girth is made with a high tech fabric that is four times more abrasion resistant than leather, wicks moisture so stays dry, is thermo regulating so stays cool, is breathable, antibacterial and hypoallergenic. Read more… The Narrow GP Girth is designed specifically to fit those horses with a narrower rib cage. To check whether a horse falls into the narrow category, measure the flat area between the horseâ€™s elbows. If the measurement is less than 20cm then the narrow version is needed to ensure the girth fits correct between the horses front legs.