Acavallo Arena AluPlus Anodized Aluminium Safety Stirrups Size:One Option Amanda Lithgow Horse Head Mug Amanda Lithgow Horse Head Mug Sun Fade Brighteners have been added The opening of the stress actuated locking and release mechanism is located a centimetre higher from the tread to ensure that the foot cannot slip out laterally by mistake and to prevent sand and dirt from delaying the opening action of the arm in case of an emergency Long holes in the tread prevent sand and dirt accumulations so that the gripping effect is not compromised and a five degree inclination of the tread helps riders to assume the correct posture relieving tension in their ankles calves knees and hips