Backup Rings

Parbak® style backup ring with a curved cross-section.

This style of backup ring is contoured on one face to minimize distortion of the o-ring when under pressure. Parbak® style backup rings should be installed with the contoured face against the o-ring, but reversal does no harm.

90A Durometer | Buna-N Rubber Material | 1 5/16 in Nominal Inner Diameter | 3/32 in Cross Section | Backup Ring

Parbak® style backup ring with a curved cross-section.

This style of backup ring is contoured on one face to minimize distortion of the o-ring when under pressure. Parbak® style backup rings should be installed with the contoured face against the o-ring, but reversal does no harm.

90A Durometer | Buna-N Rubber Material | 2 1/8 in Nominal Inner Diameter | 1/8 in Cross Section | Backup Ring

Used primarily as an anti-extrusion device for u-seals, these back-up rings combine high performance with very low friction. “ST” suffix designates a split ring.

PTFE Material | 7 3/8 in Nominal Inner Diameter | Backup Ring

Parbak® style backup ring with a curved cross-section.

This style of backup ring is contoured on one face to minimize distortion of the o-ring when under pressure. Parbak® style backup rings should be installed with the contoured face against the o-ring, but reversal does no harm.

90A Durometer | Buna-N Rubber Material | 1 13/16 in Nominal Inner Diameter | 3/32 in Cross Section | Backup Ring

Parbak® style backup ring with a curved cross-section.

This style of backup ring is contoured on one face to minimize distortion of the o-ring when under pressure. Parbak® style backup rings should be installed with the contoured face against the o-ring, but reversal does no harm.

90A Durometer | Buna-N Rubber Material | 1 1/2 in Nominal Inner Diameter | 1/8 in Cross Section | Backup Ring

Style 590 Back-up Rings feature exceptional strength and abrasion resistance along with a 53 Shore D hardness rating which makes them suitable for high pressure service where extrusion is a problem. Primarily used as a u-seal back-up, these rings can be used with o-rings. They also retrofit urethane and PTFE back-up rings, with greater performance characteristics. “S” suffix designates a split ring.

53 Shore D Durometer | Hytrel Material | 1 3/8 in Nominal Inner Diameter | 5/32 in Cross Section | Backup Ring

Solid Urethane backup ring with a flat cross-section.

95A Durometer | Urethane Material | 2 1/8 in Nominal Inner Diameter | 1/8 in Cross Section | Backup Ring

Solid Urethane backup ring with a flat cross-section.

95A Durometer | Urethane Material | 3 in Nominal Inner Diameter | 1/8 in Cross Section | Backup Ring

Commonly used with metric o-rings, these back-up rings are made of virgin PTFE unless suffix specifies otherwise.

PTFE Material | 95 MM Nominal Inner Diameter | 2.5 MM Cross Section | Backup Ring

Parbak® style backup ring with a curved cross-section.

This style of backup ring is contoured on one face to minimize distortion of the o-ring when under pressure. Parbak® style backup rings should be installed with the contoured face against the o-ring, but reversal does no harm.

90A Durometer | Buna-N Rubber Material | 4 in Nominal Inner Diameter | 1/8 in Cross Section | Backup Ring