Premium Hard Shell Chest Protector with 3DF AirFit Impact Foam The 4.5 Chest Protector is CE tested and certified as impact protection for the chest, back and flank areas. It sports a 3D multi-layer and multi-plate articulating design that ensures a good, comfortable fit. What makes it so effective as a chest protector is the use of 3DF AirFit ventilated soft impact foam. Even though it conforms to your body’s shape, it absorbs energy upon impact. The hard shell areas are made of made of high density poly ethylene (HDPE) for high impact or stone deflection.