![Design Sketch](https://products.fst.com/medialibrary/assets/designsketch_spr_0ad8e72a9f.png)
Description
The back rings of Freudenberg Sealing Technologies supplement and back up the O-ring. They act as a supporting element to prevent gap extrusion in radially sealing ISC O-rings. By expanding the use of O-rings to various shapes, back seals protect O-rings against damage.