Most often referred to as Safety Irons, but sometimes also known as "Australian Simplex" Safety Irons. This design features a pronounced loop, which should face forward and be located on the outside of the rider's foot. It is designed to allow the rider's foot to be easily released in case of a fall and prevent the rider being "hung up".
To correctly gaugue the correct stirrup size, the rider should place the ball of their foot on the stirrup bars, close to the inside, leaving a space of 25mm (1") to the outside.
Additional grip may be offered through the use of rubber treads that can be fitted to the stirrup - available for separate purchase in Black or White.