The Hallite 661 polyurethane cushion seal for pneumatic applications is designed to cushion the stroke of the piston in pneumatic cylinders by acting as a non-return valve.

Near the end of the cylinder stroke the cushion spear enters the seal and pushes it against the radial housing wall to trap air between it and the piston decelerating the piston in the process. When pressure is applied to the system to return the piston, specially designed venting grooves allow pressure to pass over the Hallite 661 to the piston.

The Hallite 661 is manufactured in Hythane® 181, Hallite’s high-performance polyurethane, for easy installation, excellent low temperature performance, and long service life.

  • Unit of measurement:
Unit of measurement:

Max pressure

16 Bar

Temp range


Max speed

  • Recomended
  • Possible
  • Not Suitable

* For fluid types marked as possible, please call our team of experts on +44 208 941 2244 to talk through your requirements and determine if this seal is the most suitable for your needs.

  Dynamic application Static application
Fluids based on mineral oil    
Any Not suitable Not suitable
Waterbased fluids    
HFA (5/95) Not suitable Not suitable
HFB (60/40 invert emulsion) Not suitable Not suitable
HFC (water glycol) Not suitable Not suitable
Water Not suitable Not suitable
Other fluid types    
Air/Nitrogen Recommended Not suitable
HFD (Phosphate ester ARYL Type) Not suitable Not suitable
Synthetic esters (HEES, HFDU) Not suitable Not suitable