Screw seals ND24 (EPA) are made of PP and are supplied with or without fitted septa made of a variety of materials. They have a 24-400 thread, a 15 mm centre hole or are closed.

These septa are temperature-resistant from -60 °C to 220 °C and have better purity than septa made of natural rubber or red rubber. However, they have less effective resealability properties and are therefore more suitable for single-injection applications. The silicone is fully coated with a silver aluminium foil.