How Does Turning Point Design Industry Leading Performance Props? When Turning Point designs a new prop for a given category, they identify the best performing OEM and Aftermarket stainless steel props in the market that fits into that category. A better aluminum & stainless steel version is designed at the same time using the same geometry & drawing. Through testing, Turning Point&&';;s engineers modify the design until it performs better than the best competitive Stainless Steel prop