The pro plt alloy stem is made from 2014 forged aluminium a high strength aluminium alloy that is commonly used in the aircraft industry due to its strength and its reliability so pro have used the same aluminium alloy to create this lightweight strong and reliable stem this stem also has an oversized 318mm clamp diameter to reduce any unwanted flex under high load by increasing strength and stiffness another great feature about this pro stem is its reversible design this allows you to us