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90A Durometer Urethane Back-Up Rings -017 Dash Size, Per Pack

Description & Features

Molded from 90A durometer urethane, these back-up rings are designed to prevent O-ring extrusion under pressure in hydraulic sealing applications. The urethane construction provides reliable extrusion resistance while remaining flexible enough to stretch for installation, returning quickly to original dimensions once seated. Sizes correspond directly to standard O-ring sizes, making selection straightforward when replacing or specifying seals in hydraulic cylinders and related assemblies.

The 90A Durometer Urethane Back-Up Rings -017 Dash Size, Per Pack from Hercules Sealing Products carry a service temperature range of -65°F to 220°F, suited for a broad range of hydraulic fluid environments. Sold in packs of 10, this dash -017 size is cataloged under Hercules part number C1BT79.

SKU: 575-017

Supplier Part Number (MPN): 575-017

Alternate Part Numbers: C1BT79, MI-01810740, MINO-00407Q30512

Specifications

Brand HERCULES® SEALING PRODUCTS	Dash Size 17	Durometer 95A	Inside Diameter 0.69 in	Material Urethane	Series 575 Series	Suitable For Use With Hydraulic and Pneumatic Cylinders	System of Measurement Imperial

Product Questions & Answers (1)

Question by: Gary E on Jul 31, 2025, 6:50 PM

these back-up rings stretch for install and then snap back to size? asking cause last batch i got from somewhere else wouldn't hold their shape after you stretched em out

Answer by: Customer Support on Aug 2, 2025, 6:37 AM

That's how these work. The 90A durometer urethane is molded to stretch during installation and return to its original dimensions once seated. That memory and recovery is a big part of what makes urethane a solid choice here versus stiffer materials that can crack or stay deformed after being worked into place.

90A Durometer Urethane Back-Up Rings -017 Dash Size, Per Pack

Description & Features

Specifications

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Product Questions & Answers (1)