Precision Molded Rubber Products

Since 1956, our manufacturing customers have relied on us to deliver a wide range of rubber assembly components for critical and demanding applications. We are your trusted source for rubber components, and our knowledge of materials and applications allows us to partner with you as a technical, problem-solving resource.

Rothkopf understands that the quality of the products you receive from your suppliers can have a major impact on your business. If you’re facing the discomfort of product failures, trust Rothkopf to provide a unique resolution tailored to your needs. We will leverage our industry expertise to ask the right questions and help you identify the root cause of the failure. With our guidance, you can make informed decisions and ensure that future designs and compatibility parameters of your rubber components meet the highest standards.

Rothkopf works hand in hand with you to maintain confidence in your brand and deliver high-quality solutions.


O-rings are one of the most common rubber components today and are used in pumps, cylinders, valves, and so much more.


Seals for a broad range of applications are available, including hydraulic, piston, shaft, wipers, buffers, wear rings, and custom-tooled.

Back-up Rings

Back-up rings work with an O-ring in higher pressure and temperature applications to prevent the O-ring from extruding into the clearance gap between sealing surfaces.


Lathe-Cut rings have a square cross-section profile, perform well in static applications, fit in O-ring grooves, and are interchangeable size-for-size with standard O-rings.

Oil Seals

Oil seals, rotary shaft seals, and V-rings are used to seal in system fluids and lubricants while keeping out dirt and contaminants. 


X-Rings have a four-lobed cross-section profile that provides twice the sealing surface of an O-ring, fit in O-ring grooves, and are interchangeable size-for-size with standard O-rings.


U-cups or Lip seals perform well in rod, piston, reciprocating, and some rotary applications.  As pressure increases, the “U” shape self-energizes to maintain sealing effectiveness.


By definition, rubber diaphragms are flexible seals that prevent unwanted transmission of substances between two places. These substances can be liquid, gasses, or solutions. They are characteristically tough and dynamic and essential in many flow control applications.

Cord Stock

Cord stock is O-ring material ready to be cut to create custom size O-rings. There is a large selection of cross-sections available and can be cut to any length you need or in standard put-up lengths. 


Our rubber gaskets can seal items, stop vibration, and reduce noise pollution.

Custom Parts

Custom parts can be anything from a unique shaped widget or just a standard style part (O-ring) with a non-standard set of dimensions.

O-Ring Sizing

The standard sizes that are typically used by manufacturers in the United States are strictly defined by Aerospace Standard AS568B, Aerospace Size Standard for O-rings.