Mill-Duty Static Seal

Series 261: Mill-Duty Static Seal

The 261 Series is a great replacement for standard large-diameter O-rings. This heavy duty static seal has a defined sealing lip manufactured from high-performance polyurethane. The square body profile prevents rolling in the groove, which is common with O-rings. The robust qualities of polyurethane allow the seal to be used without a backup ring. It is a substantial upgrade to the traditional O-ring and backup ring combination, which has been prone to rolling installation problems.



No twisting or rolling during installation

Direct retrofit to O-Ring and backup ring designs

Extrusion resistant

Abrasion-resistant polyurethane


The 261 Series Mill-Duty Static Seal is used as the primary static seal in heavy duty steel and aluminum applications and severe conditions.

Typical Applications

  • Steel and aluminum processing
  • Mobile Hydraulics
  • Hydraulic Cylinder Rebuild
  • Agricultural Hydraulics
  • Construction Equipment


The 261 Series Mill-Duty Static Seal features high-grade polyurethane. Standard materials are MP03 machined H-PU available up to 2100 mm in diameter.

Material Code
Polyurethane H-PU MP03
Nitrile NBR MN01
Fluoroelastomer FPM MF01
Temperature MP03

hydraulic oil -20…+115 -5…+240
water oil emulsions (HFA) +5…+55 +40…+130
water-glycol fl uids (HFC) -20…+55 -5….+130
polyol esters (HFD) - -
water +5…+55 +40…+130
Speed 0.5 m/s (1.6 ft/sec)
Pressure 1380 bar (20000 psi)

Note: for other materials or fluids please contact our engineering department.