Ultrathan O-rings are made from an in-house developed polyurethane compound with a very low compression set.

This low compression set made it possible to produce polyurethane O-rings. An O-ring made of polyurethane material is more resistant to extrusion than standard O-rings, so that it may be favourably used in all application with verry high pulsating pressures, or with restricted housing space not allowing the use of back-up rings.

Due to the high abrasion resistance, polyurethane O-rings are well suited for dynamic applications. very good results have been achieved e.g. with air valves sealing at pilot pistons or at the main spool dynamic sealing system. also in applications with short stroke positioning and clamping cylinders, and in valves for systems operated with poorly lubricating HFA fluids. polyurethane O-rings are used for control purposes : an example is the crossing of drill ports during which O-rings made of rubber elastomers are vulnerable to abrasive wear, significantly shortening their service life.