UHMW PE (Ultra High Molecular Weight PolyEthylene) is a high density engineered polymer. It is the highest impact strength plastic in production. It also has fantastic self-lubricity and will NOT scratch your aluminum or thin walled stainless steel tubing. This will make a night-and-day difference in aluminum bending performance.
Why would I want this? If you are bending ALUMINUM, you must use one of these or a pressure roller die (see die sets category).
Why wouldn’t I want this? If you are bending steel this will not work any better than a stock pressure die and it will wear faster.