Antares Leather running martingale attachmentPRE ORDER ITEM, SUBJECT TO STOCK. Description of the Origin running martingale attachment The running martingale attachment features 4 adjustment holes to suit different sizes and shapes of horse. The martingale has a snap hook for easy fastening to the breastplate. The specially selected French full grain leather means that the martingale is hard wearing and stretch resistant. Our martingale goes perfectly with our grained elastic breastplate.